Merge branch 'master' of https://github.com/SafeExamBrowser/seb-server.git

src/main/java/ch/ethz/seb/sebserver/gui/GuiInit.java

@@ -34,7 +34,7 @@ public class GuiInit implements ApplicationListener<ApplicationReadyEvent> {
         SEBServerInit.INIT_LOGGER.info("---->  **** GUI Service starting up... ****");
 
         SEBServerInit.INIT_LOGGER.info("---->");
-        SEBServerInit.INIT_LOGGER.info("---->  GUI Service sucessfully successfully started up!");
+        SEBServerInit.INIT_LOGGER.info("---->  GUI Service successfully successfully started up!");
         SEBServerInit.INIT_LOGGER.info("---->");
     }
 

src/main/java/ch/ethz/seb/sebserver/gui/InstitutionalAuthenticationEntryPoint.java

@@ -73,12 +73,12 @@ public final class InstitutionalAuthenticationEntryPoint implements Authenticati
         this.webserviceURIService = webserviceURIService;
         this.clientHttpRequestFactoryService = clientHttpRequestFactoryService;
 
-        String _defaultLogo = null;
+        String _defaultLogo;
         if (!Constants.NO_NAME.equals(defaultLogoFileName)) {
             try {
 
                 final String extension = ImageUploadSelection.SUPPORTED_IMAGE_FILES.stream()
-                        .filter(ext -> defaultLogoFileName.endsWith(ext))
+                        .filter(defaultLogoFileName::endsWith)
                         .findFirst()
                         .orElse(null);
 
@@ -141,7 +141,7 @@ public final class InstitutionalAuthenticationEntryPoint implements Authenticati
                                 : null);
 
                 if (log.isDebugEnabled()) {
-                    log.debug("Known and active gui entrypoint requested:", institutions);
+                    log.debug("Known and active gui entrypoint requested: {}", institutions);
                 }
 
                 final String logoImageBase64 = requestLogoImage(institutionalEndpoint);
@@ -184,9 +184,7 @@ public final class InstitutionalAuthenticationEntryPoint implements Authenticati
         }
 
         try {
-            return requestURI.substring(
+            return requestURI.substring(requestURI.lastIndexOf(Constants.SLASH) + 1);
-                    requestURI.lastIndexOf(Constants.SLASH) + 1,
-                    requestURI.length());
         } catch (final Exception e) {
             log.error("Failed to extract institutional URL suffix: {}", e.getMessage());
             return null;
@@ -231,12 +229,12 @@ public final class InstitutionalAuthenticationEntryPoint implements Authenticati
             if (exchange.getStatusCodeValue() == HttpStatus.OK.value()) {
                 return exchange.getBody();
             } else {
-                log.warn("Failed to verify insitution from requested entrypoint url: {}, response: {}",
+                log.warn("Failed to verify institution from requested entrypoint url: {}, response: {}",
                         institutionalEndpoint,
                         exchange);
             }
         } catch (final Exception e) {
-            log.warn("Failed to verify insitution from requested entrypoint url: {}",
+            log.warn("Failed to verify institution from requested entrypoint url: {}",
                     institutionalEndpoint,
                     e);
         }
@@ -245,7 +243,7 @@ public final class InstitutionalAuthenticationEntryPoint implements Authenticati
     }
 
     /** TODO this seems not to work as expected. Different Theme is only possible in RAP on different
-     * entry-points and since entry-points are statically defined within the RAPConficuration
+     * entry-points and since entry-points are statically defined within the RAPConfiguration
      * there is no possibility to apply them dynamically within an institution so far.
      *
      * @param institutionalEndpoint

src/main/java/ch/ethz/seb/sebserver/gui/RAPConfiguration.java

@@ -63,7 +63,7 @@ public class RAPConfiguration implements ApplicationConfiguration {
         }
     }
 
-    public static interface EntryPointService {
+    public interface EntryPointService {
 
         void loadLoginPage(final Composite parent);
 
@@ -160,5 +160,5 @@ public class RAPConfiguration implements ApplicationConfiguration {
             }
         }
 
-    };
+    }
 }

src/main/java/ch/ethz/seb/sebserver/gui/RAPSpringConfig.java

@@ -8,10 +8,7 @@
 
 package ch.ethz.seb.sebserver.gui;
 
-import javax.servlet.ServletContext;
+import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
-import javax.servlet.ServletContextListener;
-import javax.servlet.ServletException;
-
 import org.eclipse.rap.rwt.engine.RWTServlet;
 import org.eclipse.rap.rwt.engine.RWTServletContextListener;
 import org.slf4j.Logger;
@@ -25,7 +22,8 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.support.ReloadableResourceBundleMessageSource;
 
-import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletContextListener;
 
 @Configuration
 @GuiProfile
@@ -73,7 +71,7 @@ public class RAPSpringConfig {
 
     private static class RAPServletContextInitializer implements ServletContextInitializer {
         @Override
-        public void onStartup(final ServletContext servletContext) throws ServletException {
+        public void onStartup(final ServletContext servletContext) {
             servletContext.setInitParameter(
                     "org.eclipse.rap.applicationConfiguration",
                     RAPConfiguration.class.getName());

src/main/java/ch/ethz/seb/sebserver/gui/service/ResourceService.java

@@ -82,8 +82,8 @@ public class ResourceService {
 
     private static final String MISSING_CLIENT_PING_NAME_KEY = "MISSING";
 
-    public static final Comparator<Tuple<String>> RESOURCE_COMPARATOR = (t1, t2) -> t1._2.compareTo(t2._2);
+    public static final Comparator<Tuple<String>> RESOURCE_COMPARATOR = Comparator.comparing(t -> t._2);
-    public static final Comparator<Tuple3<String>> RESOURCE_COMPARATOR_TUPLE_3 = (t1, t2) -> t1._2.compareTo(t2._2);
+    public static final Comparator<Tuple3<String>> RESOURCE_COMPARATOR_TUPLE_3 = Comparator.comparing(t -> t._2);
 
     public static final EnumSet<EntityType> ENTITY_TYPE_EXCLUDE_MAP = EnumSet.of(
             EntityType.ADDITIONAL_ATTRIBUTES,

src/main/java/ch/ethz/seb/sebserver/gui/service/page/FieldValidationError.java

@@ -24,7 +24,7 @@ public class FieldValidationError {
     public FieldValidationError(final APIMessage apiMessage) {
         this(
                 apiMessage.messageCode,
-                apiMessage.attributes.toArray(new String[apiMessage.attributes.size()]));
+                apiMessage.attributes.toArray(new String[0]));
     }
 
     public FieldValidationError(
@@ -44,7 +44,7 @@ public class FieldValidationError {
             return new String[0];
         }
 
-        return this.attributes.toArray(new String[this.attributes.size()]);
+        return this.attributes.toArray(new String[0]);
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/page/PageContext.java

@@ -27,34 +27,34 @@ public interface PageContext {
     Logger log = LoggerFactory.getLogger(PageContext.class);
 
     /** Defines attribute keys that can be used to store attribute values within the page context state */
-    public interface AttributeKeys {
+    interface AttributeKeys {
 
-        public static final String PAGE_TEMPLATE_COMPOSER_NAME = "ATTR_PAGE_TEMPLATE_COMPOSER_NAME";
+        String PAGE_TEMPLATE_COMPOSER_NAME = "ATTR_PAGE_TEMPLATE_COMPOSER_NAME";
 
-        public static final String READ_ONLY = "READ_ONLY";
+        String READ_ONLY = "READ_ONLY";
-        public static final String READ_ONLY_FROM = "READ_ONLY_FROM";
+        String READ_ONLY_FROM = "READ_ONLY_FROM";
 
-        public static final String ENTITY_ID = "ENTITY_ID";
+        String ENTITY_ID = "ENTITY_ID";
-        public static final String PARENT_ENTITY_ID = "PARENT_ENTITY_ID";
+        String PARENT_ENTITY_ID = "PARENT_ENTITY_ID";
-        public static final String ENTITY_TYPE = "ENTITY_TYPE";
+        String ENTITY_TYPE = "ENTITY_TYPE";
-        public static final String PARENT_ENTITY_TYPE = "PARENT_ENTITY_TYPE";
+        String PARENT_ENTITY_TYPE = "PARENT_ENTITY_TYPE";
 
-        public static final String IMPORT_FROM_QUIZ_DATA = "IMPORT_FROM_QUIZ_DATA";
+        String IMPORT_FROM_QUIZ_DATA = "IMPORT_FROM_QUIZ_DATA";
 
-        public static final String COPY_AS_TEMPLATE = "COPY_AS_TEMPLATE";
+        String COPY_AS_TEMPLATE = "COPY_AS_TEMPLATE";
-        public static final String CREATE_FROM_TEMPLATE = "CREATE_FROM_TEMPLATE";
+        String CREATE_FROM_TEMPLATE = "CREATE_FROM_TEMPLATE";
 
     }
 
     /** The resource-bundle key of the generic load entity error message. */
-    public static final String GENERIC_LOAD_ERROR_TEXT_KEY = "sebserver.error.get.entity";
+    String GENERIC_LOAD_ERROR_TEXT_KEY = "sebserver.error.get.entity";
-    public static final String GENERIC_REMOVE_ERROR_TEXT_KEY = "sebserver.error.remove.entity";
+    String GENERIC_REMOVE_ERROR_TEXT_KEY = "sebserver.error.remove.entity";
-    public static final String GENERIC_SAVE_ERROR_TEXT_KEY = "sebserver.error.save.entity";
+    String GENERIC_SAVE_ERROR_TEXT_KEY = "sebserver.error.save.entity";
-    public static final String GENERIC_ACTIVATE_ERROR_TEXT_KEY = "sebserver.error.activate.entity";
+    String GENERIC_ACTIVATE_ERROR_TEXT_KEY = "sebserver.error.activate.entity";
-    public static final String GENERIC_IMPORT_ERROR_TEXT_KEY = "sebserver.error.import";
+    String GENERIC_IMPORT_ERROR_TEXT_KEY = "sebserver.error.import";
-    public static final LocTextKey SUCCESS_MSG_TITLE =
+    LocTextKey SUCCESS_MSG_TITLE =
             new LocTextKey("sebserver.page.message");
-    public static final LocTextKey UNEXPECTED_ERROR_KEY =
+    LocTextKey UNEXPECTED_ERROR_KEY =
             new LocTextKey("sebserver.error.action.unexpected.message");
 
     /** Get the I18nSupport service
@@ -84,11 +84,11 @@ public interface PageContext {
 
     /** Get a copy of this PageContext.
      *
-     * @return */
+     * @return a deep copy of this PageContext */
     PageContext copy();
 
     /** Create a copy of this PageContext with a new parent Composite.
-     * The implementation should take care of the imutability of PageContext and return a copy with the new parent
+     * The implementation should take care of the immutability of PageContext and return a copy with the new parent
      * by leave this PageContext as is.
      *
      * @param parent the new parent Composite
@@ -97,15 +97,15 @@ public interface PageContext {
 
     /** Create a copy of this PageContext with and additionally page context attributes.
      * The additionally page context attributes will get merged with them already defined
-     * The implementation should take care of the imutability of PageContext and return a copy with the merge
+     * The implementation should take care of the immutability of PageContext and return a copy with the merge
      * by leave this and the given PageContext as is.
      *
-     * @param attributes additionally page context attributes.
+     * @param otherContext the other PageContext to copy the attributes from
      * @return a copy of this PageContext with with and additionally page context attributes. */
     PageContext copyOfAttributes(PageContext otherContext);
 
     /** Adds the specified attribute to the existing page context attributes.
-     * The implementation should take care of the imutability of PageContext and return a copy
+     * The implementation should take care of the immutability of PageContext and return a copy
      * by leave this PageContext as is.
      *
      * @param key the key of the attribute
@@ -162,7 +162,7 @@ public interface PageContext {
 
     /** Create a copy of this PageContext and resets both entity keys attributes, the base and the parent EntityKey
      *
-     * @return copy of this PageContext with reseted EntityKey attributes (base and parent) */
+     * @return copy of this PageContext with reset EntityKey attributes (base and parent) */
     PageContext clearEntityKeys();
 
     /** Indicates if an attribute with the specified name exists within this PageContext
@@ -181,7 +181,7 @@ public interface PageContext {
      * block that will be executed on users OK selection.
      *
      * @param confirmMessage the localized confirm message key
-     * @param onOK callback code block that will be called on users selection */
+     * @param callback callback code block that will be called on users selection */
     void applyConfirmDialog(LocTextKey confirmMessage, final Consumer<Boolean> callback);
 
     /** This can be used to forward to a defined page.

src/main/java/ch/ethz/seb/sebserver/gui/service/page/PageDefinition.java

@@ -8,8 +8,12 @@
 
 package ch.ethz.seb.sebserver.gui.service.page;
 
+/** Defines a global SEB Server page */
 public interface PageDefinition {
 
+    /** Get the type class of the TemplateComposer that composes the page.
+     *
+     * @return the type class of the TemplateComposer that composes the page. */
     Class<? extends TemplateComposer> composer();
 
     PageContext applyPageContext(PageContext pageContext);

src/main/java/ch/ethz/seb/sebserver/gui/service/page/PageService.java

@@ -363,7 +363,7 @@ public interface PageService {
         return content;
     }
 
-    /** Used to update the crolledComposite when some if its content has dynamically changed
+    /** Used to update the scrolledComposite when some if its content has dynamically changed
      * its dimensions.
      *
      * @param composite The Component that changed its dimensions */

src/main/java/ch/ethz/seb/sebserver/gui/service/page/PageStateDefinition.java

@@ -22,9 +22,9 @@ public interface PageStateDefinition {
 
     Type type();
 
-    public Class<? extends TemplateComposer> contentPaneComposer();
+    Class<? extends TemplateComposer> contentPaneComposer();
 
-    public Class<? extends TemplateComposer> actionPaneComposer();
+    Class<? extends TemplateComposer> actionPaneComposer();
 
     Activity activityAnchor();
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/page/TemplateComposer.java

@@ -8,12 +8,20 @@
 
 package ch.ethz.seb.sebserver.gui.service.page;
 
+/** interface defining a RAP page template composer */
 public interface TemplateComposer {
 
+    /** Validate given PageContext for completeness to compose a specific  TemplateComposer implementation
+     *  Default returns always true.
+     * @param pageContext The PageContext instance to check
+     * @return true if the PageContext contains all mandatory data to compose this page template */
     default boolean validate(final PageContext pageContext) {
         return true;
     }
 
+    /** Compose a specific page template for the given PageContext
+     *
+     * @param pageContext The PageContext instance */
     void compose(PageContext pageContext);
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/page/impl/DefaultPageLayout.java

@@ -156,7 +156,7 @@ public class DefaultPageLayout implements TemplateComposer {
                 logoutSuccess.open(null);
 
                 // TODO Try to invalidate RWT's user session.
-                //      This seems to be more difficult then expected and just invalidate the HttpSession dosn't work
+                //      This seems to be more difficult then expected and just invalidate the HttpSession doesn't work
                 //      Try to send a redirect JSON to the client: https://bugs.eclipse.org/bugs/show_bug.cgi?id=388249
             });
         }
@@ -347,12 +347,8 @@ public class DefaultPageLayout implements TemplateComposer {
             final Display display = pageContext.getShell().getDisplay();
             final Image image = new Image(display, input);
             final Rectangle imageBounds = image.getBounds();
-            final int width = (imageBounds.width > LOGO_IMAGE_MAX_WIDTH)
+            final int width = Math.min(imageBounds.width, LOGO_IMAGE_MAX_WIDTH);
-                    ? LOGO_IMAGE_MAX_WIDTH
+            final int height = Math.min(imageBounds.height, LOGO_IMAGE_MAX_HEIGHT);
-                    : imageBounds.width;
-            final int height = (imageBounds.height > LOGO_IMAGE_MAX_HEIGHT)
-                    ? LOGO_IMAGE_MAX_HEIGHT
-                    : imageBounds.height;
             final ImageData imageData = image.getImageData().scaledTo(width, height);
 
             logo.setData(RWT.CUSTOM_VARIANT, "bgLogoNoImage");

src/main/java/ch/ethz/seb/sebserver/gui/service/page/impl/ModalInputDialog.java

@@ -89,7 +89,7 @@ public class ModalInputDialog<T> extends Dialog {
 
         open(
                 title,
-                (Predicate<T>) t -> true,
+                t -> true,
                 () -> {
                 }, contentComposer);
     }
@@ -130,7 +130,7 @@ public class ModalInputDialog<T> extends Dialog {
         gridData.widthHint = this.dialogWidth;
         main.setLayoutData(gridData);
 
-        final Supplier<T> valueSuppier = contentComposer.compose(main);
+        final Supplier<T> valueSupplier = contentComposer.compose(main);
         gridData.heightHint = calcDialogHeight(main);
 
         final Button ok = this.widgetFactory.buttonLocalized(shell, OK_TEXT_KEY);
@@ -138,8 +138,8 @@ public class ModalInputDialog<T> extends Dialog {
         data.widthHint = this.buttonWidth;
         ok.setLayoutData(data);
         ok.addListener(SWT.Selection, event -> {
-            if (valueSuppier != null) {
+            if (valueSupplier != null) {
-                final T result = valueSuppier.get();
+                final T result = valueSupplier.get();
                 if (callback.test(result)) {
                     shell.close();
                 }
@@ -192,9 +192,7 @@ public class ModalInputDialog<T> extends Dialog {
         final GridData data = new GridData(GridData.HORIZONTAL_ALIGN_CENTER);
         data.widthHint = this.buttonWidth;
         close.setLayoutData(data);
-        close.addListener(SWT.Selection, event -> {
+        close.addListener(SWT.Selection, event -> shell.close());
-            shell.close();
-        });
 
         finishUp(shell);
     }
@@ -216,10 +214,7 @@ public class ModalInputDialog<T> extends Dialog {
         final int availableHeight = (displayHeight < actualHeight + 100)
                 ? displayHeight - 100
                 : actualHeight;
-        final int height = (availableHeight > this.dialogHeight)
+        return Math.min(availableHeight, this.dialogHeight);
-                ? this.dialogHeight
-                : availableHeight;
-        return height;
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/page/impl/PageContextImpl.java

@@ -118,8 +118,7 @@ public class PageContextImpl implements PageContext {
 
     @Override
     public PageContext withAttribute(final String key, final String value) {
-        final Map<String, String> attrs = new HashMap<>();
+        final Map<String, String> attrs = new HashMap<>(this.attributes);
-        attrs.putAll(this.attributes);
         attrs.put(key, value);
         return new PageContextImpl(
                 this.i18nSupport,
@@ -136,11 +135,7 @@ public class PageContextImpl implements PageContext {
 
     @Override
     public String getAttribute(final String name, final String def) {
-        if (this.attributes.containsKey(name)) {
+        return this.attributes.getOrDefault(name, def);
-            return this.attributes.get(name);
-        } else {
-            return def;
-        }
     }
 
     @Override
@@ -203,8 +198,7 @@ public class PageContextImpl implements PageContext {
 
     @Override
     public PageContext removeAttribute(final String name) {
-        final Map<String, String> attrs = new HashMap<>();
+        final Map<String, String> attrs = new HashMap<>(this.attributes);
-        attrs.putAll(this.attributes);
         attrs.remove(name);
         return new PageContextImpl(
                 this.i18nSupport,
@@ -333,7 +327,7 @@ public class PageContextImpl implements PageContext {
                     this.onOK.accept(true);
                 } catch (final Exception e) {
                     log.error(
-                            "Unexpected on confirm callback execution. This should not happen, plase secure the given onOK Runnable",
+                            "Unexpected on confirm callback execution. This should not happen, please secure the given onOK Runnable",
                             e);
                     this.onOK.accept(false);
                 }

src/main/java/ch/ethz/seb/sebserver/gui/service/page/impl/PageServiceImpl.java

@@ -227,7 +227,7 @@ public class PageServiceImpl implements PageService {
                 final int dependencies = (int) entities.stream()
                         .flatMap(entity -> {
                             final RestCall<Set<EntityKey>>.RestCallBuilder builder =
-                                    restService.<Set<EntityKey>>getBuilder(
+                                    restService.getBuilder(
                                             entity.entityType(),
                                             CallType.GET_DEPENDENCIES);
 
@@ -366,7 +366,7 @@ public class PageServiceImpl implements PageService {
             final boolean logoutSuccessful = this.currentUser.logout();
 
             if (!logoutSuccessful) {
-                log.warn("Failed to logout. See logfiles for more information");
+                log.warn("Failed to logout. See log-files for more information");
             }
 
         } catch (final Exception e) {

src/main/java/ch/ethz/seb/sebserver/gui/service/push/ServerPushService.java

@@ -78,7 +78,7 @@ public class ServerPushService {
                         } catch (final Exception e) {
                             log.warn(
                                     "Failed to update on Server Push Session {}. It seems that the UISession is not available anymore. "
-                                            + "This may source from a connection interruption.",
+                                            + "This may source from a connection interruption. cause: {}",
                                     Thread.currentThread().getName(), e.getMessage());
                         }
                     });

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/download/DownloadService.java

@@ -8,16 +8,9 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.download;
 
-import java.io.IOException;
+import ch.ethz.seb.sebserver.gbl.Constants;
-import java.util.Collection;
+import ch.ethz.seb.sebserver.gbl.api.API;
-import java.util.Map;
+import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
-import java.util.function.Function;
-import java.util.stream.Collectors;
-
-import javax.servlet.ServletException;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.rap.rwt.RWT;
 import org.eclipse.rap.rwt.service.ServiceHandler;
@@ -26,10 +19,14 @@ import org.slf4j.LoggerFactory;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.stereotype.Service;
 
-import ch.ethz.seb.sebserver.gbl.Constants;
+import javax.servlet.http.HttpServletRequest;
-import ch.ethz.seb.sebserver.gbl.api.API;
+import javax.servlet.http.HttpServletResponse;
-import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
+import java.util.Collection;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 
+/** Implements a eclipse RAP ServiceHandler to handle downloads */
 @Lazy
 @Service
 @GuiProfile
@@ -54,7 +51,7 @@ public class DownloadService implements ServiceHandler {
     @Override
     public void service(
             final HttpServletRequest request,
-            final HttpServletResponse response) throws IOException, ServletException {
+            final HttpServletResponse response) {
 
         log.debug("Received download service request: {}", request.getRequestURI());
 

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/download/DownloadServiceHandler.java

@@ -11,8 +11,13 @@ package ch.ethz.seb.sebserver.gui.service.remote.download;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
+/** Interface defining a service to handle downloads */
 public interface DownloadServiceHandler {
 
+    /** Process a requested download
+     *
+     * @param request The download HttpServletRequest
+     * @param response the response to send the download to */
     void processDownload(final HttpServletRequest request, final HttpServletResponse response);
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/download/SebClientConfigDownload.java

@@ -54,7 +54,7 @@ public class SebClientConfigDownload extends AbstractDownloadServiceHandler {
             IOUtils.copyLarge(input, downloadOut);
         } catch (final IOException e) {
             log.error(
-                    "Unexpected error while streaming incomming config data from web-service to output-stream of download response: ",
+                    "Unexpected error while streaming incoming config data from web-service to output-stream of download response: ",
                     e);
         } finally {
             try {

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/download/SebExamConfigDownload.java

@@ -49,7 +49,7 @@ public class SebExamConfigDownload extends AbstractDownloadServiceHandler {
             IOUtils.copyLarge(input, downloadOut);
         } catch (final IOException e) {
             log.error(
-                    "Unexpected error while streaming incomming config data from web-service to output-stream of download response: ",
+                    "Unexpected error while streaming incoming config data from web-service to output-stream of download response: ",
                     e);
         } finally {
             try {

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/download/SebExamConfigPlaintextDownload.java

@@ -48,7 +48,7 @@ public class SebExamConfigPlaintextDownload extends AbstractDownloadServiceHandl
             IOUtils.copyLarge(input, downloadOut);
         } catch (final IOException e) {
             log.error(
-                    "Unexpected error while streaming incomming config data from web-service to output-stream of download response: ",
+                    "Unexpected error while streaming incoming config data from web-service to output-stream of download response: ",
                     e);
         } finally {
             try {

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/AbstractExportCall.java

@@ -31,9 +31,7 @@ public abstract class AbstractExportCall extends RestCall<InputStream> {
     @Override
     protected Result<InputStream> exchange(final RestCallBuilder builder) {
 
-        return Result.tryCatch(() -> {
+        return Result.tryCatch(() -> builder
-
-            return builder
                 .getRestTemplate()
                 .execute(
                         builder.buildURI(),
@@ -41,9 +39,7 @@ public abstract class AbstractExportCall extends RestCall<InputStream> {
                         (final ClientHttpRequest requestCallback) -> {
                         },
                         response -> IOUtils.toBufferedInputStream(response.getBody()),
-                            builder.getURIVariables());
+                        builder.getURIVariables()));
-
-        });
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/FormBinding.java

@@ -8,10 +8,18 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.api;
 
+/** Defines a form binding to get form parameter and values either in JSON format
+ *  or as form-url-encoded string */
 public interface FormBinding {
 
+    /** Get the form parameter and values in JSON format
+     *
+     * @return the form parameter and values in JSON format */
     String getFormAsJson();
 
+    /** Get the form parameter and values in form-url-encoded string format.
+     *
+     * @return the form parameter and values in form-url-encoded string format.*/
     String getFormUrlEncoded();
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/RestCall.java

@@ -8,14 +8,18 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.api;
 
-import java.io.IOException;
+import ch.ethz.seb.sebserver.gbl.Constants;
-import java.io.InputStream;
+import ch.ethz.seb.sebserver.gbl.api.APIMessage;
-import java.util.Arrays;
+import ch.ethz.seb.sebserver.gbl.api.EntityType;
-import java.util.HashMap;
+import ch.ethz.seb.sebserver.gbl.api.JSONMapper;
-import java.util.List;
+import ch.ethz.seb.sebserver.gbl.model.Entity;
-import java.util.Map;
+import ch.ethz.seb.sebserver.gbl.model.Page;
-import java.util.function.Function;
+import ch.ethz.seb.sebserver.gbl.model.PageSortOrder;
-
+import ch.ethz.seb.sebserver.gbl.util.Result;
+import ch.ethz.seb.sebserver.gbl.util.Utils;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -32,20 +36,13 @@ import org.springframework.web.client.RestClientResponseException;
 import org.springframework.web.client.RestTemplate;
 import org.springframework.web.util.UriComponentsBuilder;
 
-import com.fasterxml.jackson.core.JsonParseException;
+import java.io.IOException;
-import com.fasterxml.jackson.core.JsonProcessingException;
+import java.io.InputStream;
-import com.fasterxml.jackson.core.type.TypeReference;
+import java.util.Arrays;
-import com.fasterxml.jackson.databind.JsonMappingException;
+import java.util.HashMap;
-
+import java.util.List;
-import ch.ethz.seb.sebserver.gbl.Constants;
+import java.util.Map;
-import ch.ethz.seb.sebserver.gbl.api.APIMessage;
+import java.util.function.Function;
-import ch.ethz.seb.sebserver.gbl.api.EntityType;
-import ch.ethz.seb.sebserver.gbl.api.JSONMapper;
-import ch.ethz.seb.sebserver.gbl.model.Entity;
-import ch.ethz.seb.sebserver.gbl.model.Page;
-import ch.ethz.seb.sebserver.gbl.model.PageSortOrder;
-import ch.ethz.seb.sebserver.gbl.util.Result;
-import ch.ethz.seb.sebserver.gbl.util.Utils;
 
 public abstract class RestCall<T> {
 
@@ -173,7 +170,7 @@ public abstract class RestCall<T> {
     }
 
     private Result<T> handleRestCallError(final ResponseEntity<String> responseEntity)
-            throws IOException, JsonParseException, JsonMappingException {
+            throws IOException {
 
         final RestCallError restCallError =
                 new RestCallError("Response Entity: " + responseEntity.toString());
@@ -225,6 +222,7 @@ public abstract class RestCall<T> {
             this.uriComponentsBuilder = builder.uriComponentsBuilder;
             this.httpHeaders = builder.httpHeaders;
             this.body = builder.body;
+            this.streamingBody = builder.streamingBody;
             this.queryParams = new LinkedMultiValueMap<>(builder.queryParams);
             this.uriVariables = new HashMap<>(builder.uriVariables);
         }

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/RestCallError.java

@@ -49,9 +49,7 @@ public class RestCallError extends RuntimeException implements APIMessageError {
     public boolean isFieldValidationError() {
         return this.errors
                 .stream()
-                .filter(error -> APIMessage.ErrorMessage.FIELD_VALIDATION.isOf(error))
+                .anyMatch(APIMessage.ErrorMessage.FIELD_VALIDATION::isOf);
-                .findFirst()
-                .isPresent();
     }
 
     @Override

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/RestService.java

@@ -52,7 +52,7 @@ public interface RestService {
      * NOTE not all RestCall can be get within this method. Only the ones that have a defined CallType
      *
      * @param entityType The EntityType of the RestCall
-     * @param callType The CallType of the RestCall (not UNDEFINDED)
+     * @param callType The CallType of the RestCall (not UNDEFINED)
      * @return RestCall instance */
     <T> RestCall<T> getRestCall(EntityType entityType, CallType callType);
 
@@ -65,7 +65,7 @@ public interface RestService {
     /** Get a certain RestCallBuilder by EntityType and CallType.
      *
      * @param entityType The EntityType of the RestCall to get a builder for
-     * @param callType The CallType of the RestCall to get a builder for (not UNDEFINDED)
+     * @param callType The CallType of the RestCall to get a builder for (not UNDEFINED)
      * @return RestCallBuilder instance to build a dedicated call and execute it */
     <T> RestCall<T>.RestCallBuilder getBuilder(
             EntityType entityType,

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/api/useraccount/SaveUserAccount.java

@@ -21,6 +21,7 @@ import ch.ethz.seb.sebserver.gbl.model.user.UserInfo;
 import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
 import ch.ethz.seb.sebserver.gui.service.remote.webservice.api.RestCall;
 
+
 @Lazy
 @Component
 @GuiProfile

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/auth/CurrentUser.java

@@ -119,17 +119,15 @@ public class CurrentUser {
                 return userInfo
                         .getRoles()
                         .stream()
-                        .map(roleName -> UserRole.valueOf(roleName))
+                        .map(UserRole::valueOf)
                         .map(role -> new RoleTypeKey(entityType, role))
                         .map(key -> this.privileges.get(key))
-                        .filter(priv -> (priv != null) && priv.hasGrant(
+                        .anyMatch(privilege -> (privilege != null) && privilege.hasGrant(
                                 userInfo.uuid,
                                 userInfo.institutionId,
                                 privilegeType,
                                 institutionId,
-                                ownerId))
+                                ownerId));
-                        .findFirst()
-                        .isPresent();
             } catch (final Exception e) {
                 log.error("Failed to verify privilege: PrivilegeType {} EntityType {}",
                         privilegeType, entityType, e);
@@ -149,17 +147,15 @@ public class CurrentUser {
                 final UserInfo userInfo = get();
                 return userInfo.getRoles()
                         .stream()
-                        .map(roleName -> UserRole.valueOf(roleName))
+                        .map(UserRole::valueOf)
                         .map(role -> new RoleTypeKey(entityType, role))
                         .map(key -> this.privileges.get(key))
-                        .filter(priv -> (priv != null) && priv.hasGrant(
+                        .anyMatch(privilege -> (privilege != null) && privilege.hasGrant(
                                 userInfo.uuid,
                                 userInfo.institutionId,
                                 privilegeType,
                                 grantEntity.getInstitutionId(),
-                                grantEntity.getOwnerId()))
+                                grantEntity.getOwnerId()));
-                        .findFirst()
-                        .isPresent();
             } catch (final Exception e) {
                 log.error("Failed to verify privilege: PrivilegeType {} EntityType {}",
                         privilegeType, entityType, e);
@@ -234,9 +230,9 @@ public class CurrentUser {
                     if (privileges != null) {
                         this.privileges = privileges
                                 .stream()
-                                .reduce(new HashMap<RoleTypeKey, Privilege>(),
+                                .reduce(new HashMap<>(),
-                                        (map, priv) -> {
+                                        (map, privilege) -> {
-                                            map.put(priv.roleTypeKey, priv);
+                                            map.put(privilege.roleTypeKey, privilege);
                                             return map;
                                         },
                                         (map1, map2) -> {

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/auth/OAuth2AuthorizationContextHolder.java

@@ -8,15 +8,12 @@
 
 package ch.ethz.seb.sebserver.gui.service.remote.webservice.auth;
 
-import java.io.IOException;
+import ch.ethz.seb.sebserver.ClientHttpRequestFactoryService;
-import java.net.URI;
+import ch.ethz.seb.sebserver.gbl.model.user.UserInfo;
-import java.nio.charset.Charset;
+import ch.ethz.seb.sebserver.gbl.model.user.UserRole;
-import java.util.Arrays;
+import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
-import java.util.Collections;
+import ch.ethz.seb.sebserver.gbl.util.Result;
-import java.util.List;
+import ch.ethz.seb.sebserver.gbl.util.Utils;
-
-import javax.servlet.http.HttpSession;
-
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -44,12 +41,13 @@ import org.springframework.web.client.ResponseExtractor;
 import org.springframework.web.client.RestClientException;
 import org.springframework.web.client.RestTemplate;
 
-import ch.ethz.seb.sebserver.ClientHttpRequestFactoryService;
+import javax.servlet.http.HttpSession;
-import ch.ethz.seb.sebserver.gbl.model.user.UserInfo;
+import java.io.IOException;
-import ch.ethz.seb.sebserver.gbl.model.user.UserRole;
+import java.net.URI;
-import ch.ethz.seb.sebserver.gbl.profile.GuiProfile;
+import java.nio.charset.StandardCharsets;
-import ch.ethz.seb.sebserver.gbl.util.Result;
+import java.util.Arrays;
-import ch.ethz.seb.sebserver.gbl.util.Utils;
+import java.util.Collections;
+import java.util.List;
 
 @Lazy
 @Component
@@ -171,7 +169,7 @@ public class OAuth2AuthorizationContextHolder implements AuthorizationContextHol
             this.restTemplate.setErrorHandler(new ErrorHandler(this.resource));
             this.restTemplate
                     .getMessageConverters()
-                    .add(0, new StringHttpMessageConverter(Charset.forName("UTF-8")));
+                    .add(0, new StringHttpMessageConverter(StandardCharsets.UTF_8));
 
             this.revokeTokenURI = webserviceURIService.getOAuthRevokeTokenURI();
             this.currentUserURI = webserviceURIService.getCurrentUserRequestURI();

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/auth/SEBServerAuthorizationContext.java

@@ -34,7 +34,7 @@ public interface SEBServerAuthorizationContext {
      *
      * @param username the username for login
      * @param password the password for login
-     * @return */
+     * @return true if login was successful, false if no */
     boolean login(String username, CharSequence password);
 
     /** Requests a logout on SEB Server webservice if a user is currently logged in

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/auth/WebserviceConnectionData.java

@@ -14,29 +14,29 @@ public class WebserviceConnectionData {
 
     final String id;
     final String webserviceProtocol;
-    final String webserviceServerAdress;
+    final String webserviceServerAddress;
     final String webserviceServerPort;
     final String webserviceAPIPath;
-    final String webserviceServerAddress;
+    final String webserviceServerURL;
 
     private final UriComponentsBuilder webserviceURIBuilder;
 
     protected WebserviceConnectionData(
             final String id,
             final String webserviceProtocol,
-            final String webserviceServerAdress,
+            final String webserviceServerAddress,
             final String webserviceServerPort,
             final String webserviceAPIPath) {
 
         this.id = id;
         this.webserviceProtocol = webserviceProtocol;
-        this.webserviceServerAdress = webserviceServerAdress;
+        this.webserviceServerAddress = webserviceServerAddress;
         this.webserviceServerPort = webserviceServerPort;
         this.webserviceAPIPath = webserviceAPIPath;
 
-        this.webserviceServerAddress = webserviceProtocol + "://" + webserviceServerAdress + ":" + webserviceServerPort;
+        this.webserviceServerURL = webserviceProtocol + "://" + webserviceServerAddress + ":" + webserviceServerPort;
         this.webserviceURIBuilder = UriComponentsBuilder
-                .fromHttpUrl(webserviceProtocol + "://" + webserviceServerAdress)
+                .fromHttpUrl(webserviceProtocol + "://" + webserviceServerAddress)
                 .port(webserviceServerPort)
                 .path(webserviceAPIPath);
     }
@@ -49,8 +49,8 @@ public class WebserviceConnectionData {
         return this.webserviceProtocol;
     }
 
-    public String getWebserviceServerAdress() {
+    public String getWebserviceServerAddress() {
-        return this.webserviceServerAdress;
+        return this.webserviceServerAddress;
     }
 
     public String getWebserviceServerPort() {
@@ -61,8 +61,8 @@ public class WebserviceConnectionData {
         return this.webserviceAPIPath;
     }
 
-    public String getWebserviceServerAddress() {
+    public String getWebserviceServerURL() {
-        return this.webserviceServerAddress;
+        return this.webserviceServerURL;
     }
 
     public UriComponentsBuilder getWebserviceURIBuilder() {
@@ -101,8 +101,8 @@ public class WebserviceConnectionData {
         builder.append(this.id);
         builder.append(", webserviceProtocol=");
         builder.append(this.webserviceProtocol);
-        builder.append(", webserviceServerAdress=");
+        builder.append(", webserviceServerAddress=");
-        builder.append(this.webserviceServerAdress);
+        builder.append(this.webserviceServerAddress);
         builder.append(", webserviceServerPort=");
         builder.append(this.webserviceServerPort);
         builder.append(", webserviceAPIPath=");

src/main/java/ch/ethz/seb/sebserver/gui/service/remote/webservice/auth/WebserviceURIService.java

@@ -25,15 +25,15 @@ public class WebserviceURIService {
 
     public WebserviceURIService(
             @Value("${sebserver.gui.webservice.protocol}") final String webserviceProtocol,
-            @Value("${sebserver.gui.webservice.address}") final String webserviceServerAdress,
+            @Value("${sebserver.gui.webservice.address}") final String webserviceServerAddress,
             @Value("${sebserver.gui.webservice.port}") final String webserviceServerPort,
             @Value("${server.servlet.context-path}") final String servletContextPath,
             @Value("${sebserver.gui.webservice.apipath}") final String webserviceAPIPath) {
 
         this.servletContextPath = servletContextPath;
-        this.webserviceServerAddress = webserviceProtocol + "://" + webserviceServerAdress + ":" + webserviceServerPort;
+        this.webserviceServerAddress = webserviceProtocol + "://" + webserviceServerAddress + ":" + webserviceServerPort;
         this.webserviceURIBuilder = UriComponentsBuilder
-                .fromHttpUrl(webserviceProtocol + "://" + webserviceServerAdress)
+                .fromHttpUrl(webserviceProtocol + "://" + webserviceServerAddress)
                 .port(webserviceServerPort)
                 .path(servletContextPath)
                 .path(webserviceAPIPath);

src/main/java/ch/ethz/seb/sebserver/gui/service/session/ClientConnectionDetails.java

@@ -49,12 +49,10 @@ public class ClientConnectionDetails {
 
     private static final int NUMBER_OF_NONE_INDICATOR_ROWS = 3;
 
-    private final PageService pageService;
     private final ResourceService resourceService;
-    private final Exam exam;
     private final EnumMap<IndicatorType, IndicatorData> indicatorMapping;
     private final RestCall<ClientConnectionData>.RestCallBuilder restCallBuilder;
-    private final FormHandle<?> formhandle;
+    private final FormHandle<?> formHandle;
     private final ColorData colorData;
 
     private ClientConnectionData connectionData = null;
@@ -69,9 +67,7 @@ public class ClientConnectionDetails {
 
         final Display display = pageContext.getRoot().getDisplay();
 
-        this.pageService = pageService;
         this.resourceService = pageService.getResourceService();
-        this.exam = exam;
         this.restCallBuilder = restCallBuilder;
         this.colorData = new ColorData(display);
         this.indicatorMapping = IndicatorData.createFormIndicators(
@@ -80,12 +76,12 @@ public class ClientConnectionDetails {
                 this.colorData,
                 NUMBER_OF_NONE_INDICATOR_ROWS);
 
-        final FormBuilder formBuilder = this.pageService.formBuilder(pageContext)
+        final FormBuilder formBuilder = pageService.formBuilder(pageContext)
                 .readonly(true)
                 .addField(FormBuilder.text(
                         QuizData.QUIZ_ATTR_NAME,
                         EXAM_NAME_TEXT_KEY,
-                        this.exam.getName()))
+                        exam.getName()))
                 .addField(FormBuilder.text(
                         Domain.CLIENT_CONNECTION.ATTR_EXAM_USER_SESSION_ID,
                         CONNECTION_ID_TEXT_KEY,
@@ -112,7 +108,7 @@ public class ClientConnectionDetails {
                         .withDefaultLabel(indData.indicator.name))
                         .addEmptyCell());
 
-        this.formhandle = formBuilder.build();
+        this.formHandle = formBuilder.build();
     }
 
     public void updateData() {
@@ -136,7 +132,7 @@ public class ClientConnectionDetails {
             return;
         }
 
-        final Form form = this.formhandle.getForm();
+        final Form form = this.formHandle.getForm();
         form.setFieldValue(
                 Domain.CLIENT_CONNECTION.ATTR_EXAM_USER_SESSION_ID,
                 this.connectionData.clientConnection.userSessionId);

src/main/java/ch/ethz/seb/sebserver/gui/service/session/ClientConnectionTable.java

@@ -371,7 +371,7 @@ public final class ClientConnectionTable {
     private void sortTable() {
         this.tableMapping = this.tableMapping.entrySet()
                 .stream()
-                .sorted((e1, e2) -> e1.getValue().compareTo(e2.getValue()))
+                .sorted(Entry.comparingByValue())
                 .collect(Collectors.toMap(
                         Entry::getKey,
                         Entry::getValue,
@@ -398,13 +398,12 @@ public final class ClientConnectionTable {
             final String attribute = this.resourceService
                     .getCurrentUser()
                     .getAttribute(USER_SESSION_STATUS_FILTER_ATTRIBUTE);
-            if (attribute != null) {
             this.statusFilter.clear();
+            if (attribute != null) {
                 Arrays.asList(StringUtils.split(attribute, Constants.LIST_SEPARATOR))
                         .forEach(name -> this.statusFilter.add(ConnectionStatus.valueOf(name)));
 
             } else {
-                this.statusFilter.clear();
                 this.statusFilter.add(ConnectionStatus.DISABLED);
             }
         } catch (final Exception e) {
@@ -460,7 +459,7 @@ public final class ClientConnectionTable {
         }
 
         void updateData(final TableItem tableItem) {
-            tableItem.setText(0, getConnectionIdentifer());
+            tableItem.setText(0, getConnectionIdentifier());
             tableItem.setText(1, getConnectionAddress());
             tableItem.setText(2, getStatusName());
         }
@@ -533,7 +532,7 @@ public final class ClientConnectionTable {
         public int compareTo(final UpdatableTableItem other) {
             return Comparator.comparingInt(UpdatableTableItem::statusWeight)
                     .thenComparingInt(UpdatableTableItem::thresholdsWeight)
-                    .thenComparing(UpdatableTableItem::getConnectionIdentifer)
+                    .thenComparing(UpdatableTableItem::getConnectionIdentifier)
                     .compare(this, other);
         }
 
@@ -580,7 +579,7 @@ public final class ClientConnectionTable {
             return Constants.EMPTY_NOTE;
         }
 
-        String getConnectionIdentifer() {
+        String getConnectionIdentifier() {
             if (this.connectionData != null && this.connectionData.clientConnection.userSessionId != null) {
                 return this.connectionData.clientConnection.userSessionId;
             }
@@ -608,10 +607,7 @@ public final class ClientConnectionTable {
                 final IndicatorData indicatorData =
                         ClientConnectionTable.this.indicatorMapping.get(indicatorValue.getType());
 
-                if (indicatorData == null) {
+                if (indicatorData != null) {
-                    log.error("No IndicatorData of type: {} found", indicatorValue.getType());
-                } else {
-
                     final double value = indicatorValue.getValue();
                     final int indicatorWeight = IndicatorData.getWeight(indicatorData, value);
                     if (this.indicatorWeights[indicatorData.index] != indicatorWeight) {

src/main/java/ch/ethz/seb/sebserver/gui/service/session/IndicatorData.java

@@ -8,18 +8,17 @@
 
 package ch.ethz.seb.sebserver.gui.service.session;
 
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.EnumMap;
-
-import org.eclipse.swt.graphics.Color;
-import org.eclipse.swt.widgets.Display;
-
 import ch.ethz.seb.sebserver.gbl.model.exam.Indicator;
 import ch.ethz.seb.sebserver.gbl.model.exam.Indicator.IndicatorType;
 import ch.ethz.seb.sebserver.gbl.model.exam.Indicator.Threshold;
 import ch.ethz.seb.sebserver.gbl.util.Utils;
+import org.eclipse.swt.graphics.Color;
+import org.eclipse.swt.widgets.Display;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.EnumMap;
 
 final class IndicatorData {
 
@@ -47,13 +46,13 @@ final class IndicatorData {
 
         this.thresholdColor = new ThresholdColor[indicator.thresholds.size()];
         final ArrayList<Threshold> sortedThresholds = new ArrayList<>(indicator.thresholds);
-        Collections.sort(sortedThresholds, (t1, t2) -> t1.value.compareTo(t2.value));
+        sortedThresholds.sort(Comparator.comparing(t -> t.value));
         for (int i = 0; i < indicator.thresholds.size(); i++) {
             this.thresholdColor[i] = new ThresholdColor(sortedThresholds.get(i), display, colorData);
         }
     }
 
-    static final EnumMap<IndicatorType, IndicatorData> createFormIndicators(
+    static EnumMap<IndicatorType, IndicatorData> createFormIndicators(
             final Collection<Indicator> indicators,
             final Display display,
             final ColorData colorData,
@@ -73,7 +72,7 @@ final class IndicatorData {
         return indicatorMapping;
     }
 
-    static final int getWeight(final IndicatorData indicatorData, final double value) {
+    static int getWeight(final IndicatorData indicatorData, final double value) {
         for (int j = 0; j < indicatorData.thresholdColor.length; j++) {
             if (value < indicatorData.thresholdColor[j].value) {
                 return (j == 0) ? -1 : j - 1;

src/main/java/ch/ethz/seb/sebserver/gui/service/session/InstructionProcessor.java

@@ -92,13 +92,11 @@ public class InstructionProcessor {
                 StringUtils.join(connectionTokens, Constants.LIST_SEPARATOR),
                 null);
 
-        processInstruction(() -> {
+        processInstruction(() -> this.restService.getBuilder(PropagateInstruction.class)
-            return this.restService.getBuilder(PropagateInstruction.class)
                 .withURIVariable(API.PARAM_MODEL_ID, String.valueOf(examId))
                 .withBody(clientInstruction)
                 .call()
-                    .getOrThrow();
+                .getOrThrow(),
-        },
                 pageContext);
 
     }
@@ -116,7 +114,6 @@ public class InstructionProcessor {
                         ConnectionStatus.AUTHENTICATED));
 
         if (connectionTokens.isEmpty()) {
-            // TOOD message
             return;
         }
 
@@ -126,15 +123,13 @@ public class InstructionProcessor {
                     connectionTokens);
         }
 
-        processInstruction(() -> {
+        processInstruction(() -> this.restService.getBuilder(DisableClientConnection.class)
-            return this.restService.getBuilder(DisableClientConnection.class)
                 .withURIVariable(API.PARAM_MODEL_ID, String.valueOf(examId))
                 .withFormParam(
                         Domain.CLIENT_CONNECTION.ATTR_CONNECTION_TOKEN,
                         StringUtils.join(connectionTokens, Constants.LIST_SEPARATOR))
                 .call()
-                    .getOrThrow();
+                .getOrThrow(),
-        },
                 pageContext);
 
     }

src/main/java/ch/ethz/seb/sebserver/gui/table/EntityTable.java

@@ -96,12 +96,12 @@ public class EntityTable<ROW extends Entity> {
     private final BiConsumer<TableItem, ROW> rowDecorator;
     private final Consumer<Set<ROW>> selectionListener;
 
-    int pageNumber = 1;
+    int pageNumber;
     int pageSize;
     String sortColumn = null;
     PageSortOrder sortOrder = PageSortOrder.ASCENDING;
     boolean columnsWithSameWidth = true;
-    boolean hideNavigation = false;
+    boolean hideNavigation;
 
     EntityTable(
             final String name,
@@ -149,13 +149,10 @@ public class EntityTable<ROW extends Entity> {
         this.rowDecorator = rowDecorator;
         this.selectionListener = selectionListener;
         this.pageSize = pageSize;
-        this.filter =
+        this.filter = columns
-                columns
                 .stream()
-                        .map(column -> column.getFilterAttribute())
+                .map(ColumnDefinition::getFilterAttribute)
-                        .filter(Objects::nonNull)
+                .anyMatch(Objects::nonNull) ? new TableFilter<>(this) : null;
-                        .findFirst()
-                        .isPresent() ? new TableFilter<>(this) : null;
 
         this.table = this.widgetFactory.tableLocalized(this.composite);
         final GridLayout gridLayout = new GridLayout(columns.size(), true);
@@ -207,17 +204,15 @@ public class EntityTable<ROW extends Entity> {
             }
 
             for (int i = 0; i < columns.size(); i++) {
-                final Rectangle itemBoundes = item.getBounds(i);
+                final Rectangle itemBounds = item.getBounds(i);
-                if (itemBoundes.contains(point)) {
+                if (itemBounds.contains(point)) {
                     handleCellSelection(item, i);
                     return;
                 }
             }
         });
 
-        this.table.addListener(SWT.Selection, event -> {
+        this.table.addListener(SWT.Selection, event -> this.notifySelectionChange());
-            this.notifySelectionChange();
-        });
 
         this.navigator = new TableNavigator(this);
 
@@ -375,8 +370,7 @@ public class EntityTable<ROW extends Entity> {
             return Collections.emptySet();
         }
 
-        return Arrays.asList(selection)
+        return Arrays.stream(selection)
-                .stream()
                 .map(this::getRowData)
                 .collect(Collectors.toSet());
     }
@@ -391,8 +385,7 @@ public class EntityTable<ROW extends Entity> {
             return Collections.emptySet();
         }
 
-        return Arrays.asList(selection)
+        return Arrays.stream(selection)
-                .stream()
                 .filter(item -> grantCheck == null || grantCheck.test(getRowData(item)))
                 .map(this::getRowDataId)
                 .collect(Collectors.toSet());
@@ -415,8 +408,7 @@ public class EntityTable<ROW extends Entity> {
     }
 
     private TableColumn getTableColumn(final String name) {
-        return Arrays.asList(this.table.getColumns())
+        return Arrays.stream(this.table.getColumns())
-                .stream()
                 .filter(col -> {
                     @SuppressWarnings("unchecked")
                     final ColumnDefinition<ROW> def = (ColumnDefinition<ROW>) col.getData(COLUMN_DEFINITION);
@@ -541,7 +533,7 @@ public class EntityTable<ROW extends Entity> {
                     .filter(c -> c.getWidthProportion() > 0)
                     .reduce(0,
                             (acc, c) -> acc + c.getWidthProportion(),
-                            (acc1, acc2) -> acc1 + acc2);
+                            Integer::sum);
 
             // The unit size either with proportion or for a entire column if all columns are equal in size
             final int columnUnitSize = (pSize > 0)

src/main/java/ch/ethz/seb/sebserver/gui/table/TableBuilder.java

@@ -100,7 +100,7 @@ public class TableBuilder<ROW extends Entity> {
         return this;
     }
 
-    public TableBuilder<ROW> withMultiselection() {
+    public TableBuilder<ROW> withMultiSelection() {
         this.type |= SWT.MULTI;
         return this;
     }

src/main/java/ch/ethz/seb/sebserver/gui/table/TableFilter.java

@@ -49,7 +49,7 @@ public class TableFilter<ROW extends Entity> {
     private static final LocTextKey DATE_TO_TEXT = new LocTextKey("sebserver.overall.date.to");
     private static final LocTextKey ALL_TEXT = new LocTextKey("sebserver.overall.status.all");
 
-    public static enum CriteriaType {
+    public enum CriteriaType {
         TEXT,
         SINGLE_SELECTION,
         DATE,
@@ -82,7 +82,7 @@ public class TableFilter<ROW extends Entity> {
     public MultiValueMap<String, String> getFilterParameter() {
         return this.components
                 .stream()
-                .reduce(new LinkedMultiValueMap<String, String>(),
+                .reduce(new LinkedMultiValueMap<>(),
                         (map, comp) -> comp.putFilterParameter(map),
                         (map1, map2) -> {
                             map1.putAll(map2);
@@ -92,8 +92,7 @@ public class TableFilter<ROW extends Entity> {
 
     public void reset() {
         this.components
-                .stream()
+                .forEach(FilterComponent::reset);
-                .forEach(comp -> comp.reset());
     }
 
     private void buildComponents() {
@@ -158,7 +157,7 @@ public class TableFilter<ROW extends Entity> {
                                 .append(Constants.FORM_URL_ENCODED_NAME_VALUE_SEPARATOR)
                                 .append(filter.getValue())
                                 .append(Constants.LIST_SEPARATOR),
-                        (sb1, sb2) -> sb1.append(sb2));
+                        StringBuilder::append);
         if (builder.length() > 0) {
             builder.deleteCharAt(builder.length() - 1);
         }
@@ -171,22 +170,19 @@ public class TableFilter<ROW extends Entity> {
         }
 
         try {
-            Arrays.asList(StringUtils.split(
+            Arrays.stream(StringUtils.split(
                     attribute,
                     Constants.LIST_SEPARATOR_CHAR))
-                    .stream()
                     .map(nameValue -> StringUtils.split(
                             nameValue,
                             Constants.FORM_URL_ENCODED_NAME_VALUE_SEPARATOR))
-                    .forEach(nameValue -> {
+                    .forEach(nameValue -> this.components
-                        this.components
                             .stream()
                             .filter(filter -> nameValue[0].equals(filter.attribute.columnName))
                             .findFirst()
                             .ifPresent(filter -> filter.setValue((nameValue.length > 1)
                                     ? nameValue[1]
-                                        : StringUtils.EMPTY));
+                                    : StringUtils.EMPTY)));
-                    });
         } catch (final Exception e) {
             log.error("Failed to set filter attributes: ", e);
         }
@@ -208,9 +204,7 @@ public class TableFilter<ROW extends Entity> {
                 ImageIcon.SEARCH,
                 inner,
                 new LocTextKey("sebserver.overall.action.filter"),
-                event -> {
+                event -> this.entityTable.applyFilter());
-                    this.entityTable.applyFilter();
-                });
         imageButton.setLayoutData(gridData);
         final Label imageButton2 = this.entityTable.widgetFactory.imageButton(
                 ImageIcon.CANCEL,
@@ -276,7 +270,7 @@ public class TableFilter<ROW extends Entity> {
         }
     }
 
-    private class NullFilter extends FilterComponent {
+    private static class NullFilter extends FilterComponent {
 
         private Label label;
 
@@ -493,7 +487,6 @@ public class TableFilter<ROW extends Entity> {
     private class DateRange extends FilterComponent {
 
         private Composite innerComposite;
-        //private final GridData rw1 = new GridData(SWT.FILL, SWT.FILL, true, true);
         private DateTime fromDateSelector;
         private DateTime toDateSelector;
         private DateTime fromTimeSelector;

src/main/java/ch/ethz/seb/sebserver/gui/table/TableNavigator.java

@@ -68,7 +68,7 @@ public class TableNavigator {
 
         if (numberOfPages > 1) {
             createBackwardLabel(pageNumber > 1, pageNumber, numNav);
-            final int pageNavSize = (numberOfPages > PAGE_NAV_SIZE) ? PAGE_NAV_SIZE : numberOfPages;
+            final int pageNavSize = Math.min(numberOfPages, PAGE_NAV_SIZE);
             final int half = pageNavSize / 2;
             int start = pageNumber - half;
             if (start < 1) {
@@ -107,14 +107,12 @@ public class TableNavigator {
 
         final GridData rowData = new GridData(22, 16);
         final Label pageLabel = new Label(parent, SWT.NONE);
-        pageLabel.setText(" " + String.valueOf(page) + " ");
+        pageLabel.setText(" " + page + " ");
         pageLabel.setLayoutData(rowData);
         pageLabel.setAlignment(SWT.CENTER);
         if (selectable) {
             pageLabel.setData(RWT.CUSTOM_VARIANT, CustomVariant.LIST_NAVIGATION.key);
-            pageLabel.addListener(SWT.MouseDown, event -> {
+            pageLabel.addListener(SWT.MouseDown, event -> this.entityTable.selectPage(page));
-                this.entityTable.selectPage(page);
-            });
         }
     }
 
@@ -131,9 +129,7 @@ public class TableNavigator {
         forward.setLayoutData(rowData);
         forward.setAlignment(SWT.CENTER);
         if (visible) {
-            forward.addListener(SWT.MouseDown, event -> {
+            forward.addListener(SWT.MouseDown, event -> this.entityTable.selectPage(pageNumber + 1));
-                this.entityTable.selectPage(pageNumber + 1);
-            });
         } else {
             forward.setVisible(false);
         }
@@ -144,9 +140,7 @@ public class TableNavigator {
         end.setLayoutData(rowData);
         end.setAlignment(SWT.CENTER);
         if (visible) {
-            end.addListener(SWT.MouseDown, event -> {
+            end.addListener(SWT.MouseDown, event -> this.entityTable.selectPage(numberOfPages));
-                this.entityTable.selectPage(numberOfPages);
-            });
         } else {
             end.setVisible(false);
         }
@@ -164,9 +158,7 @@ public class TableNavigator {
         start.setAlignment(SWT.CENTER);
         start.setData(RWT.CUSTOM_VARIANT, CustomVariant.LIST_NAVIGATION.key);
         if (visible) {
-            start.addListener(SWT.MouseDown, event -> {
+            start.addListener(SWT.MouseDown, event -> this.entityTable.selectPage(1));
-                this.entityTable.selectPage(1);
-            });
         } else {
             start.setVisible(false);
         }
@@ -177,9 +169,7 @@ public class TableNavigator {
         backward.setAlignment(SWT.CENTER);
         backward.setData(RWT.CUSTOM_VARIANT, CustomVariant.LIST_NAVIGATION.key);
         if (visible) {
-            backward.addListener(SWT.MouseDown, event -> {
+            backward.addListener(SWT.MouseDown, event -> this.entityTable.selectPage(pageNumber - 1));
-                this.entityTable.selectPage(pageNumber - 1);
-            });
         } else {
             backward.setVisible(false);
         }

src/main/java/ch/ethz/seb/sebserver/gui/widget/FileUploadSelection.java

@@ -166,10 +166,8 @@ public class FileUploadSelection extends Composite {
     private boolean fileSupported(final String fileName) {
         return this.supportedFileExtensions
                 .stream()
-                .filter(fileType -> fileName.toUpperCase(Locale.ROOT)
+                .anyMatch(fileType -> fileName.toUpperCase(Locale.ROOT)
-                        .endsWith(fileType.toUpperCase(Locale.ROOT)))
+                        .endsWith(fileType.toUpperCase(Locale.ROOT)));
-                .findFirst()
-                .isPresent();
     }
 
     private final class InputReceiver extends FileUploadReceiver {

src/main/java/ch/ethz/seb/sebserver/gui/widget/GridTable.java

@@ -157,7 +157,7 @@ public class GridTable extends Composite {
         return StringUtils.join(
                 this.rows
                         .stream()
-                        .map(row -> row.getValue())
+                        .map(Row::getValue)
                         .collect(Collectors.toList()),
                 Constants.LIST_SEPARATOR);
     }
@@ -209,10 +209,9 @@ public class GridTable extends Composite {
                     .stream()
                     .reduce(0,
                             (i, c2) -> i + c2.columnDef.widthFactor,
-                            (i1, i2) -> i1 + i2);
+                            Integer::sum);
 
             this.columns
-                    .stream()
                     .forEach(c -> c.header.widthHint = c.columnDef.widthFactor * widthUnit);
 
             super.layout(true, true);
@@ -273,7 +272,7 @@ public class GridTable extends Composite {
             this.defaultValue = defaultValue;
         }
 
-        public static final ColumnDef fromString(
+        public static ColumnDef fromString(
                 final String string,
                 final Map<String, String> defaultValueMap) {
 

src/main/java/ch/ethz/seb/sebserver/gui/widget/ImageUploadSelection.java

@@ -48,10 +48,7 @@ public final class ImageUploadSelection extends Composite {
     private static final long serialVersionUID = 368264811155804533L;
     private static final Logger log = LoggerFactory.getLogger(ImageUploadSelection.class);
 
-    public static final Set<String> SUPPORTED_IMAGE_FILES = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(
+    public static final Set<String> SUPPORTED_IMAGE_FILES = Set.of(".png", ".jpg", ".jpeg");
-            ".png",
-            ".jpg",
-            ".jpeg")));
 
     private final ServerPushService serverPushService;
 
@@ -152,12 +149,12 @@ public final class ImageUploadSelection extends Composite {
         setImage(this, input);
     }
 
-    private static final boolean uploadInProgress(final ServerPushContext context) {
+    private static boolean uploadInProgress(final ServerPushContext context) {
         final ImageUploadSelection imageUpload = (ImageUploadSelection) context.getAnchor();
         return imageUpload.loadNewImage && !imageUpload.imageLoaded;
     }
 
-    private static final void update(final ServerPushContext context) {
+    private static void update(final ServerPushContext context) {
         final ImageUploadSelection imageUpload = (ImageUploadSelection) context.getAnchor();
         if (imageUpload.imageBase64 != null
                 && imageUpload.loadNewImage
@@ -181,12 +178,8 @@ public final class ImageUploadSelection extends Composite {
 
         final Image image = new Image(imageUpload.imageCanvas.getDisplay(), input);
         final Rectangle imageBounds = image.getBounds();
-        final int width = (imageBounds.width > imageUpload.maxWidth)
+        final int width = Math.min(imageBounds.width, imageUpload.maxWidth);
-                ? imageUpload.maxWidth
+        final int height = Math.min(imageBounds.height, imageUpload.maxHeight);
-                : imageBounds.width;
-        final int height = (imageBounds.height > imageUpload.maxHeight)
-                ? imageUpload.maxHeight
-                : imageBounds.height;
         final ImageData imageData = image.getImageData().scaledTo(width, height);
         imageUpload.imageCanvas.setBackgroundImage(new Image(imageUpload.imageCanvas.getDisplay(), imageData));
     }
@@ -194,10 +187,8 @@ public final class ImageUploadSelection extends Composite {
     private static boolean fileSupported(final String fileName) {
         return SUPPORTED_IMAGE_FILES
                 .stream()
-                .filter(fileType -> fileName.toUpperCase(Locale.ROOT)
+                .anyMatch(fileType -> fileName.toUpperCase(Locale.ROOT)
-                        .endsWith(fileType.toUpperCase(Locale.ROOT)))
+                        .endsWith(fileType.toUpperCase(Locale.ROOT)));
-                .findFirst()
-                .isPresent();
     }
 
     private final class ImageReceiver extends FileUploadReceiver {

src/main/java/ch/ethz/seb/sebserver/gui/widget/MultiSelectionCheckbox.java

@@ -8,12 +8,11 @@
 
 package ch.ethz.seb.sebserver.gui.widget;
 
-import java.util.Arrays;
+import ch.ethz.seb.sebserver.gbl.Constants;
-import java.util.LinkedHashMap;
+import ch.ethz.seb.sebserver.gbl.util.Tuple;
-import java.util.List;
+import ch.ethz.seb.sebserver.gbl.util.Tuple3;
-import java.util.Map;
+import ch.ethz.seb.sebserver.gbl.util.Utils;
-import java.util.stream.Collectors;
+import ch.ethz.seb.sebserver.gui.service.page.PageService;
-
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.layout.GridData;
@@ -22,11 +21,10 @@ import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Listener;
 
-import ch.ethz.seb.sebserver.gbl.Constants;
+import java.util.Arrays;
-import ch.ethz.seb.sebserver.gbl.util.Tuple;
+import java.util.LinkedHashMap;
-import ch.ethz.seb.sebserver.gbl.util.Tuple3;
+import java.util.List;
-import ch.ethz.seb.sebserver.gbl.util.Utils;
+import java.util.Map;
-import ch.ethz.seb.sebserver.gui.service.page.PageService;
 
 public final class MultiSelectionCheckbox extends Composite implements Selection {
 
@@ -121,7 +119,7 @@ public final class MultiSelectionCheckbox extends Composite implements Selection
                         .stream()
                         .filter(Button::getSelection)
                         .map(button -> (String) button.getData(OPTION_VALUE))
-                        .collect(Collectors.toList()).toArray());
+                        .toArray());
     }
 
     @Override

src/main/java/ch/ethz/seb/sebserver/gui/widget/MultiSelectionCombo.java

@@ -8,13 +8,9 @@
 
 package ch.ethz.seb.sebserver.gui.widget;
 
-import java.util.ArrayList;
+import ch.ethz.seb.sebserver.gbl.Constants;
-import java.util.Arrays;
+import ch.ethz.seb.sebserver.gbl.util.Tuple;
-import java.util.Collection;
+import ch.ethz.seb.sebserver.gui.service.page.PageService;
-import java.util.List;
-import java.util.Optional;
-import java.util.stream.Collectors;
-
 import org.apache.commons.lang3.StringUtils;
 import org.eclipse.rap.rwt.widgets.DropDown;
 import org.eclipse.swt.SWT;
@@ -29,9 +25,10 @@ import org.eclipse.swt.widgets.Text;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import ch.ethz.seb.sebserver.gbl.Constants;
+import java.util.ArrayList;
-import ch.ethz.seb.sebserver.gbl.util.Tuple;
+import java.util.Arrays;
-import ch.ethz.seb.sebserver.gui.service.page.PageService;
+import java.util.List;
+import java.util.Optional;
 
 public final class MultiSelectionCombo extends Composite implements Selection {
 
@@ -75,12 +72,8 @@ public final class MultiSelectionCombo extends Composite implements Selection {
         this.textCell = new GridData(SWT.LEFT, SWT.CENTER, true, true);
         this.textInput.setLayoutData(this.textCell);
         this.dropDown = new DropDown(this.textInput, SWT.NONE);
-        this.textInput.addListener(SWT.FocusIn, event -> {
+        this.textInput.addListener(SWT.FocusIn, event -> openDropDown());
-            openDropDown();
+        this.textInput.addListener(SWT.Modify, event -> openDropDown());
-        });
-        this.textInput.addListener(SWT.Modify, event -> {
-            openDropDown();
-        });
         this.dropDown.addListener(SWT.Selection, event -> {
             final int selectionIndex = this.dropDown.getSelectionIndex();
             if (selectionIndex >= 0) {
@@ -98,12 +91,10 @@ public final class MultiSelectionCombo extends Composite implements Selection {
             this.dropDown.setVisible(false);
             return;
         }
-        final Collection<String> items = this.availableValues
+        this.dropDown.setItems(this.availableValues
                 .stream()
                 .filter(it -> it._2 != null && it._2.startsWith(text))
-                .map(t -> t._2)
+                .map(t -> t._2).toArray(String[]::new));
-                .collect(Collectors.toList());
-        this.dropDown.setItems(items.toArray(new String[items.size()]));
         this.dropDown.setSelectionIndex(0);
         this.dropDown.setVisible(true);
     }
@@ -132,8 +123,7 @@ public final class MultiSelectionCombo extends Composite implements Selection {
             return;
         }
 
-        Arrays.asList(StringUtils.split(keys, Constants.LIST_SEPARATOR))
+        Arrays.stream(StringUtils.split(keys, Constants.LIST_SEPARATOR))
-                .stream()
                 .map(this::itemForId)
                 .forEach(this::addSelection);
     }
@@ -159,7 +149,6 @@ public final class MultiSelectionCombo extends Composite implements Selection {
     public void clear() {
         this.selectedValues.clear();
         this.selectionControls
-                .stream()
                 .forEach(Control::dispose);
         this.selectionControls.clear();
         this.availableValues.clear();
@@ -176,9 +165,7 @@ public final class MultiSelectionCombo extends Composite implements Selection {
         label.setData(OPTION_VALUE, item._2);
         final GridData textCell = new GridData(SWT.LEFT, SWT.CENTER, true, true);
         label.setLayoutData(textCell);
-        label.addListener(SWT.MouseDoubleClick, event -> {
+        label.addListener(SWT.MouseDoubleClick, this::removeComboSelection);
-            removeComboSelection(event);
-        });
         this.selectionControls.add(label);
 
         this.availableValues.remove(item);
@@ -217,8 +204,7 @@ public final class MultiSelectionCombo extends Composite implements Selection {
 
     private void adaptColumnWidth(final Event event) {
         try {
-            final int currentTableWidth = this.getClientArea().width;
+            this.textCell.widthHint = this.getClientArea().width;
-            this.textCell.widthHint = currentTableWidth;
             this.layout();
         } catch (final Exception e) {
             log.warn("Failed to adaptColumnWidth: ", e);
@@ -230,11 +216,7 @@ public final class MultiSelectionCombo extends Composite implements Selection {
                 .stream()
                 .filter(it -> it._2 != null && it._2.equals(name))
                 .findFirst();
-        if (findFirst.isPresent()) {
+        return findFirst.orElse(null);
-            return findFirst.get();
-        }
-
-        return null;
     }
 
     private Tuple<String> itemForId(final String id) {
@@ -242,11 +224,7 @@ public final class MultiSelectionCombo extends Composite implements Selection {
                 .stream()
                 .filter(it -> it._1 != null && it._1.equals(id))
                 .findFirst();
-        if (findFirst.isPresent()) {
+        return findFirst.orElse(null);
-            return findFirst.get();
-        }
-
-        return null;
     }
 
 }

src/main/java/ch/ethz/seb/sebserver/gui/widget/RadioSelection.java

@@ -99,7 +99,7 @@ public final class RadioSelection extends Composite implements Selection {
         return this.radioButtons
                 .values()
                 .stream()
-                .filter(button -> button.getSelection())
+                .filter(Button::getSelection)
                 .findFirst()
                 .map(button -> (String) button.getData(OPTION_VALUE))
                 .orElse(null);
@@ -109,7 +109,6 @@ public final class RadioSelection extends Composite implements Selection {
     public void clear() {
         this.radioButtons
                 .values()
-                .stream()
                 .forEach(button -> button.setSelection(false));
 
     }

src/main/java/ch/ethz/seb/sebserver/gui/widget/Selection.java

@@ -17,7 +17,7 @@ import ch.ethz.seb.sebserver.gbl.util.Tuple;
 
 public interface Selection {
 
-    static final String OPTION_VALUE = "OPTION_VALUE";
+    String OPTION_VALUE = "OPTION_VALUE";
 
     enum Type {
         SINGLE,

src/main/java/ch/ethz/seb/sebserver/gui/widget/SingleSelection.java

@@ -87,7 +87,7 @@ public final class SingleSelection extends Combo implements Selection {
     @Override
     public void clear() {
         super.clearSelection();
-        super.setItems(this.valueMapping.toArray(new String[this.valueMapping.size()]));
+        super.setItems(this.valueMapping.toArray(new String[0]));
     }
 
     @Override

src/main/java/ch/ethz/seb/sebserver/gui/widget/WidgetFactory.java

@@ -123,7 +123,7 @@ public class WidgetFactory {
         private ImageData image = null;
         private ImageData greyedImage = null;
 
-        private ImageIcon(final String fileName) {
+        ImageIcon(final String fileName) {
             this.fileName = fileName;
         }
 
@@ -199,7 +199,7 @@ public class WidgetFactory {
 
         public final String key;
 
-        private CustomVariant(final String key) {
+        CustomVariant(final String key) {
             this.key = key;
         }
     }
@@ -268,7 +268,7 @@ public class WidgetFactory {
      * @param parent The parent Composite
      * @return the scrolled Composite to add the form content */
     public Composite createPopupScrollComposite(final Composite parent) {
-        final Composite grid = PageService.createManagedVScrolledComposite(
+        return PageService.createManagedVScrolledComposite(
                 parent,
                 scrolledComposite -> {
                     final Composite g = new Composite(scrolledComposite, SWT.NONE);
@@ -277,7 +277,6 @@ public class WidgetFactory {
                     return g;
                 },
                 false);
-        return grid;
     }
 
     public Composite createWarningPanel(final Composite parent) {
@@ -733,7 +732,7 @@ public class WidgetFactory {
                 new FileUploadSelection(parent, this.i18nSupport, readonly);
 
         if (supportedFiles != null) {
-            supportedFiles.forEach(ext -> fileUploadSelection.withSupportFor(ext));
+            supportedFiles.forEach(fileUploadSelection::withSupportFor);
         }
         return fileUploadSelection;
     }

src/main/java/ch/ethz/seb/sebserver/webservice/WebserviceInit.java

@@ -57,13 +57,6 @@ public class WebserviceInit implements ApplicationListener<ApplicationReadyEvent
 
         SEBServerInit.INIT_LOGGER.info("---->  **** Webservice starting up... ****");
 
-        SEBServerInit.INIT_LOGGER.info("----> ");
-        SEBServerInit.INIT_LOGGER.info("----> Init Database with flyway...");
-        SEBServerInit.INIT_LOGGER.info("----> TODO ");
-
-        // TODO integration of Flyway for database initialization and migration:  https://flywaydb.org
-        //      see also https://flywaydb.org/getstarted/firststeps/api
-
         SEBServerInit.INIT_LOGGER.info("----> ");
         SEBServerInit.INIT_LOGGER.info("----> Intitialize Services...");
         SEBServerInit.INIT_LOGGER.info("----> ");

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/lms/LmsAPIService.java

@@ -23,6 +23,7 @@ import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup;
 import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetupTestResult;
 import ch.ethz.seb.sebserver.gbl.util.Result;
 import ch.ethz.seb.sebserver.webservice.servicelayer.dao.FilterMap;
+import org.joda.time.DateTimeZone;
 
 /** Defines the LMS API access service interface with all functionality needed to access
  * a LMS API within a given LmsSetup configuration.
@@ -101,12 +102,12 @@ public interface LmsAPIService {
     static Predicate<QuizData> quizFilterPredicate(final FilterMap filterMap) {
         final String name = filterMap.getQuizName();
         final DateTime from = filterMap.getQuizFromTime();
-        //final DateTime now = DateTime.now(DateTimeZone.UTC);
         return q -> {
             final boolean nameFilter = StringUtils.isBlank(name) || (q.name != null && q.name.contains(name));
             final boolean startTimeFilter =
                     (from == null) || (q.startTime != null && (q.startTime.isEqual(from) || q.startTime.isAfter(from)));
-            return nameFilter && startTimeFilter /* && endTimeFilter */;
+            final boolean currentlyRunning = DateTime.now(DateTimeZone.UTC).isBefore(q.endTime);
+            return nameFilter && (startTimeFilter || currentlyRunning) ;
         };
     }
 

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/sebconfig/ClientConfigService.java

@@ -60,10 +60,10 @@ public interface ClientConfigService {
             unless = "#result.hasError()")
     Result<ClientDetails> getClientConfigDetails(String clientName);
 
-    @CacheEvict(
+    /** Internally used to check OAuth2 access for a active SebClientConfig.
-            cacheNames = EXAM_CLIENT_DETAILS_CACHE,
+     *
-            allEntries = true)
+     * @param config the SebClientConfig to check access
-    @EventListener(BulkActionEvent.class)
+     * @return true if the system was able to gain an access token for the client. False otherwise
-    void flushClientConfigData(BulkActionEvent event);
+     */
-
+    boolean checkAccess(SebClientConfig config);
 }

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/sebconfig/impl/ClientConfigServiceImpl.java

@@ -10,8 +10,7 @@ package ch.ethz.seb.sebserver.webservice.servicelayer.sebconfig.impl;
 
 import ch.ethz.seb.sebserver.WebSecurityConfig;
 import ch.ethz.seb.sebserver.gbl.Constants;
-import ch.ethz.seb.sebserver.gbl.api.API.BulkActionType;
+import ch.ethz.seb.sebserver.gbl.api.API;
-import ch.ethz.seb.sebserver.gbl.api.EntityType;
 import ch.ethz.seb.sebserver.gbl.model.EntityKey;
 import ch.ethz.seb.sebserver.gbl.model.institution.Institution;
 import ch.ethz.seb.sebserver.gbl.model.sebconfig.SebClientConfig;
@@ -19,8 +18,6 @@ import ch.ethz.seb.sebserver.gbl.profile.WebServiceProfile;
 import ch.ethz.seb.sebserver.gbl.util.Result;
 import ch.ethz.seb.sebserver.gbl.util.Utils;
 import ch.ethz.seb.sebserver.webservice.WebserviceInfo;
-import ch.ethz.seb.sebserver.webservice.servicelayer.bulkaction.impl.BulkAction;
-import ch.ethz.seb.sebserver.webservice.servicelayer.bulkaction.impl.BulkActionEvent;
 import ch.ethz.seb.sebserver.webservice.servicelayer.client.ClientCredentialService;
 import ch.ethz.seb.sebserver.webservice.servicelayer.client.ClientCredentials;
 import ch.ethz.seb.sebserver.webservice.servicelayer.dao.InstitutionDAO;
@@ -38,12 +35,21 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.annotation.Lazy;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.security.oauth2.common.OAuth2AccessToken;
 import org.springframework.security.oauth2.provider.ClientDetails;
 import org.springframework.security.oauth2.provider.client.BaseClientDetails;
 import org.springframework.security.oauth2.provider.token.TokenStore;
 import org.springframework.stereotype.Service;
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.RestTemplate;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -51,6 +57,7 @@ import java.io.OutputStream;
 import java.io.PipedInputStream;
 import java.io.PipedOutputStream;
 import java.nio.charset.StandardCharsets;
+import java.util.Base64;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.UUID;
@@ -316,19 +323,48 @@ public class ClientConfigServiceImpl implements ClientConfigService {
     }
 
     @Override
-    public void flushClientConfigData(final BulkActionEvent event) {
+    public boolean checkAccess(SebClientConfig config) {
-        try {
+        if(!config.isActive()) {
-            final BulkAction bulkAction = event.getBulkAction();
+            return false;
-
-            if (bulkAction.type == BulkActionType.DEACTIVATE ||
-                    bulkAction.type == BulkActionType.HARD_DELETE) {
-
-                bulkAction.extractKeys(EntityType.SEB_CLIENT_CONFIGURATION)
-                        .forEach(this::flushClientConfigData);
         }
 
-        } catch (final Exception e) {
+        try {
-            log.error("Unexpected error while trying to flush ClientConfig data ", e);
+            RestTemplate restTemplate = new RestTemplate();
+            String externalServerURL = webserviceInfo.getExternalServerURL() +
+                    API.OAUTH_TOKEN_ENDPOINT;
+
+            MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
+            headers.add(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_FORM_URLENCODED_VALUE);
+            ClientCredentials credentials = sebClientConfigDAO
+                    .getSebClientCredentials(config.getModelId())
+                    .getOrThrow();
+            CharSequence plainClientSecret = clientCredentialService.getPlainClientSecret(credentials);
+            String basicAuth = credentials.clientId +
+                    String.valueOf(Constants.COLON) +
+                    plainClientSecret;
+            String encoded = Base64.getEncoder()
+                    .encodeToString(basicAuth.getBytes());
+
+            headers.add(HttpHeaders.AUTHORIZATION, "Basic " + encoded);
+            HttpEntity<String> entity = new HttpEntity<>(
+                    "grant_type=client_credentials&scope=read write",
+                    headers);
+
+            ResponseEntity<String> exchange = restTemplate.exchange(
+                    externalServerURL,
+                    HttpMethod.POST,
+                    entity,
+                    String.class);
+
+            if (exchange.getStatusCode().value() == HttpStatus.OK.value()) {
+                return true;
+            } else {
+                log.warn("Failed to check access SebClientConfig {} response: {}", config, exchange.getStatusCode());
+                return false;
+            }
+        } catch (Exception e) {
+            log.warn("Failed to check access for SebClientConfig: {} cause: {}", config, e.getMessage());
+            return false;
         }
     }
 

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/ClientIndicatorFactory.java

@@ -9,6 +9,7 @@
 package ch.ethz.seb.sebserver.webservice.servicelayer.session.impl;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -93,6 +94,17 @@ public class ClientIndicatorFactory {
                 final PingIntervalClientIndicator pingIndicator = this.applicationContext
                         .getBean(PingIntervalClientIndicator.class);
                 pingIndicator.hidden = true;
+                final Indicator indicator = new Indicator(
+                        null,
+                        clientConnection.examId,
+                        "hidden_ping_indicator",
+                        IndicatorType.LAST_PING,
+                        "",
+                        Arrays.asList(new Indicator.Threshold(5000d, "")));
+                pingIndicator.init(
+                        indicator,
+                        clientConnection.id,
+                        this.enableCaching);
                 result.add(pingIndicator);
             }
 

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/PingIntervalClientIndicator.java

@@ -38,7 +38,6 @@ public final class PingIntervalClientIndicator extends AbstractPingIndicator {
 
     long pingErrorThreshold;
     boolean missingPing = false;
-
     boolean hidden = false;
 
     public PingIntervalClientIndicator(final ClientEventExtensionMapper clientEventExtensionMapper) {

src/main/java/ch/ethz/seb/sebserver/webservice/weblayer/api/ClientEventController.java

@@ -95,6 +95,8 @@ public class ClientEventController extends ReadonlyEntityController<ClientEvent,
             filterMap.putIfAbsent(API.PARAM_INSTITUTION_ID, String.valueOf(institutionId));
         }
 
+        try {
+
             return this.paginationService.getPage(
                     pageNumber,
                     pageSize,
@@ -102,6 +104,10 @@ public class ClientEventController extends ReadonlyEntityController<ClientEvent,
                     getSQLTableOfEntity().name(),
                     () -> this.clientEventDAO.allMatchingExtended(filterMap, this::hasReadAccess))
                     .getOrThrow();
+        } catch (Exception e) {
+            e.printStackTrace();
+            throw e;
+        }
     }
 
     @Override
@@ -118,7 +124,7 @@ public class ClientEventController extends ReadonlyEntityController<ClientEvent,
     protected GrantEntity toGrantEntity(final ClientEvent entity) {
         return this.examDAO
                 .byClientConnection(entity.connectionId)
-                .getOrThrow();
+                .get();
     }
 
     @Override

src/main/java/ch/ethz/seb/sebserver/webservice/weblayer/api/SebClientConfigController.java

@@ -39,6 +39,7 @@ import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.RestTemplate;
 
 import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletResponse;
@@ -144,6 +145,15 @@ public class SebClientConfigController extends ActivatableEntityController<SebCl
                 .map(this::checkPasswordMatch);
     }
 
+    @Override
+    protected Result<SebClientConfig> notifySaved(SebClientConfig entity) {
+        if (entity.isActive()) {
+            // try to get access token for SEB client
+            sebClientConfigService.checkAccess(entity);
+        }
+        return super.notifySaved(entity);
+    }
+
     private SebClientConfig checkPasswordMatch(final SebClientConfig entity) {
         Collection<APIMessage> errors = new ArrayList<>();
         if (entity.hasEncryptionSecret() && !entity.encryptSecret.equals(entity.encryptSecretConfirm)) {

src/main/java/ch/ethz/seb/sebserver/webservice/weblayer/oauth/DefaultTokenServicesFallback.java

@@ -17,6 +17,7 @@ import org.springframework.security.oauth2.common.OAuth2AccessToken;
 import org.springframework.security.oauth2.provider.OAuth2Authentication;
 import org.springframework.security.oauth2.provider.token.DefaultTokenServices;
 
+// TODO check if we can apply some caching here to get better performance for SEB client connection attempts
 public class DefaultTokenServicesFallback extends DefaultTokenServices {
 
     private static final Logger log = LoggerFactory.getLogger(DefaultTokenServicesFallback.class);
@@ -29,22 +30,22 @@ public class DefaultTokenServicesFallback extends DefaultTokenServices {
             return super.createAccessToken(authentication);
         } catch (final DuplicateKeyException e) {
 
-            log.info(
+            log.warn(
-                    "Catched DuplicateKeyException, try to handle it by trying to get the already stored access token after waited some time");
+                    "Caught DuplicateKeyException, try to handle it by trying to get the already stored access token after waited some time");
 
             final String clientName = authentication.getName();
             if (StringUtils.isNotBlank(clientName)) {
 
-                // wait a second...
+                // wait some time...
                 try {
-                    Thread.sleep(1000);
+                    Thread.sleep(500);
                 } catch (final InterruptedException e1) {
                     log.warn("Failed to sleep: {}", e1.getMessage());
                 }
 
                 final OAuth2AccessToken accessToken = this.getAccessToken(authentication);
                 if (accessToken != null) {
-                    log.info("Found original accees token for client: {} token: {}", clientName, accessToken);
+                    log.debug("Found original access token for client: {} ", clientName);
                     return accessToken;
                 }
             }

src/main/resources/config/application-dev-ws.properties

@@ -25,7 +25,7 @@ sebserver.init.adminaccount.gen-on-init=false
 sebserver.webservice.distributed=false
 sebserver.webservice.http.scheme=http
 sebserver.webservice.http.external.servername=
-sebserver.webservice.http.external.port=
+sebserver.webservice.http.external.port=${server.port}
 sebserver.webservice.http.redirect.gui=/gui
 
 

src/main/resources/config/sql/base/V2__insert_data_v1_0.sql

@@ -175,7 +175,7 @@ INSERT INTO configuration_attribute VALUES
     (304, 'enablePrivateClipboard', 'CHECKBOX', null, null, null, null, 'true'),
     (305, 'enableLogging', 'CHECKBOX', null, null, null, null, 'false'),
     (306, 'logDirectoryWin', 'TEXT_FIELD', null, null, null, null, ''),
-    (307, 'logDirectoryOSX', 'TEXT_FIELD', null, null, null, null, 'NSTemporaryDirectory'),
+    (307, 'logDirectoryOSX', 'TEXT_FIELD', null, null, null, null, 'F'),
     (308, 'minMacOSVersion', 'SINGLE_SELECTION', null, '0,1,2,3,4,5,6,7', null, null, '0'),
     (309, 'enableAppSwitcherCheck', 'CHECKBOX', null, null, null, null, 'true'),
     (310, 'forceAppFolderInstall', 'CHECKBOX', null, null, null, null, 'true'),
@@ -263,7 +263,7 @@ INSERT INTO configuration_attribute VALUES
     (927, 'mobileStatusBarAppearanceExtended', 'SINGLE_SELECTION', null, '0,1,2,3,4', null, null, '1'),
     (928, 'newBrowserWindowShowURL', 'SINGLE_SELECTION', null, '0,1,2,3', null, null, '1'),
     (929, 'pinEmbeddedCertificates', 'CHECKBOX', null, null, null, null, 'false'),
-    (930, 'sendBrowserExamKey', 'CHECKBOX', null, null, null, null, 'false'),
+    (930, 'sendBrowserExamKey', 'CHECKBOX', null, null, null, null, 'true'),
     (931, 'showNavigationButtons', 'CHECKBOX', null, null, null, null, 'false'),
     (932, 'showScanQRCodeButton', 'CHECKBOX', null, null, null, null, 'false'),
     (933, 'startResource', 'TEXT_FIELD', null, null, null, null, ''),

src/test/resources/data-test-additional.sql

@@ -198,7 +198,7 @@ INSERT IGNORE INTO configuration_attribute VALUES
     (304, 'enablePrivateClipboard', 'CHECKBOX', null, null, null, null, 'true'),
     (305, 'enableLogging', 'CHECKBOX', null, null, null, null, 'false'),
     (306, 'logDirectoryWin', 'TEXT_FIELD', null, null, null, null, ''),
-    (307, 'logDirectoryOSX', 'TEXT_FIELD', null, null, null, null, 'NSTemporaryDirectory'),
+    (307, 'logDirectoryOSX', 'TEXT_FIELD', null, null, null, null, ''),
     (308, 'minMacOSVersion', 'SINGLE_SELECTION', null, '0,1,2,3,4,5,6,7', null, null, '0'),
     (309, 'enableAppSwitcherCheck', 'CHECKBOX', null, null, null, null, 'true'),
     (310, 'forceAppFolderInstall', 'CHECKBOX', null, null, null, null, 'true'),
@@ -286,7 +286,7 @@ INSERT IGNORE INTO configuration_attribute VALUES
     (927, 'mobileStatusBarAppearanceExtended', 'SINGLE_SELECTION', null, '0,1,2,3,4', null, null, '1'),
     (928, 'newBrowserWindowShowURL', 'SINGLE_SELECTION', null, '0,1,2,3', null, null, '1'),
     (929, 'pinEmbeddedCertificates', 'CHECKBOX', null, null, null, null, 'false'),
-    (930, 'sendBrowserExamKey', 'CHECKBOX', null, null, null, null, 'false'),
+    (930, 'sendBrowserExamKey', 'CHECKBOX', null, null, null, null, 'true'),
     (931, 'showNavigationButtons', 'CHECKBOX', null, null, null, null, 'false'),
     (932, 'showScanQRCodeButton', 'CHECKBOX', null, null, null, null, 'false'),
     (933, 'startResource', 'TEXT_FIELD', null, null, null, null, ''),