--- a/gwt-client/src/main/java/org/dive4elements/river/client/shared/model/DefaultCollectionItem.java	Wed Sep 26 15:48:05 2018 +0200
+++ b/gwt-client/src/main/java/org/dive4elements/river/client/shared/model/DefaultCollectionItem.java	Thu Sep 27 18:06:26 2018 +0200
@@ -11,7 +11,6 @@
 import java.util.List;
 import java.util.Map;
 
-
 /**
  * The default implementation of a CollectionItem (artifact).
  *
@@ -19,6 +18,8 @@
  */
 public class DefaultCollectionItem implements CollectionItem {
 
+    private static final long serialVersionUID = 1L;
+
     /** The identifier that specifies the artifact related to this item. */
     protected String identifier;
 
@@ -31,52 +32,46 @@
     /** The map of datanames to data values. */
     protected Map<String, String> data;
 
-
     /**
      * An empty constructor.
      */
     public DefaultCollectionItem() {
     }
 
-
     /**
      * The default constructor to create a new CollectionItem related to an
      * artifact with output modes.
      *
-     * @param identifier The identifier of an artifact.
-     * @param outputModes The output modes supported by this item.
+     * @param identifier
+     *            The identifier of an artifact.
+     * @param outputModes
+     *            The output modes supported by this item.
      */
-    public DefaultCollectionItem(
-        String           identifier,
-        String           hash,
-        List<OutputMode> modes,
-        Map<String,String> data
-    ) {
-        this.identifier  = identifier;
-        this.hash        = hash;
+    public DefaultCollectionItem(final String identifier, final String hash, final List<OutputMode> modes, final Map<String, String> data) {
+        this.identifier = identifier;
+        this.hash = hash;
         this.outputModes = modes;
-        this.data        = data;
+        this.data = data;
     }
 
-
-
+    @Override
     public String identifier() {
-        return identifier;
+        return this.identifier;
     }
 
-
+    @Override
     public String hash() {
-        return hash;
+        return this.hash;
     }
 
-
+    @Override
     public List<OutputMode> getOutputModes() {
-        return outputModes;
+        return this.outputModes;
     }
 
-
-    public List<Facet> getFacets(String outputmode) {
-        for (OutputMode mode: outputModes) {
+    @Override
+    public List<Facet> getFacets(final String outputmode) {
+        for (final OutputMode mode : this.outputModes) {
             if (outputmode.equals(mode.getName())) {
                 // TODO Return facets, but facets are not implemented for
                 // OutputModes yet!
@@ -86,11 +81,12 @@
         return null;
     }
 
-
     /**
      * Returns artifact data.
+     * 
      * @return key/value data map
      */
+    @Override
     public Map<String, String> getData() {
         return this.data;
     }