diff --git a/tools/cooja/apps/mrm/java/org/contikios/mrm/MRMVisualizerSkin.java b/tools/cooja/apps/mrm/java/org/contikios/mrm/MRMVisualizerSkin.java
index 58f1fab1a..12c27187d 100644
--- a/tools/cooja/apps/mrm/java/org/contikios/mrm/MRMVisualizerSkin.java
+++ b/tools/cooja/apps/mrm/java/org/contikios/mrm/MRMVisualizerSkin.java
@@ -56,6 +56,7 @@ public class MRMVisualizerSkin implements VisualizerSkin {
   private Simulation simulation = null;
   private Visualizer visualizer = null;
 
+  @Override
   public void setActive(Simulation simulation, Visualizer vis) {
     if (!(simulation.getRadioMedium() instanceof MRM)) {
       logger.fatal("Cannot activate MRM skin for unknown radio medium: " + simulation.getRadioMedium());
@@ -65,6 +66,7 @@ public class MRMVisualizerSkin implements VisualizerSkin {
     this.visualizer = vis;
   }
 
+  @Override
   public void setInactive() {
     if (simulation == null) {
       /* Skin was never activated */
@@ -72,6 +74,7 @@ public class MRMVisualizerSkin implements VisualizerSkin {
     }
   }
 
+  @Override
   public Color[] getColorOf(Mote mote) {
     if (visualizer.getSelectedMotes().contains(mote)) {
       return new Color[] { Color.CYAN };
@@ -79,6 +82,7 @@ public class MRMVisualizerSkin implements VisualizerSkin {
     return null;
   }
 
+  @Override
   public void paintBeforeMotes(Graphics g) {
     Set<Mote> selectedMotes = visualizer.getSelectedMotes();
     if (simulation == null || selectedMotes == null) {
@@ -120,9 +124,11 @@ public class MRMVisualizerSkin implements VisualizerSkin {
         }
         final Radio dRadio = d.getInterfaces().getRadio();
         TxPair txPair = new RadioPair() {
+          @Override
           public Radio getFromRadio() {
             return selectedMote.getInterfaces().getRadio();
           }
+          @Override
           public Radio getToRadio() {
             return dRadio;
           }
@@ -154,9 +160,11 @@ public class MRMVisualizerSkin implements VisualizerSkin {
     }
   }
 
+  @Override
   public void paintAfterMotes(Graphics g) {
   }
 
+  @Override
   public Visualizer getVisualizer() {
     return visualizer;
   }
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/Visualizer.java b/tools/cooja/java/org/contikios/cooja/plugins/Visualizer.java
index 6b36a0ebf..86df645d6 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/Visualizer.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/Visualizer.java
@@ -249,12 +249,15 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     viewMenu = new JMenu("View");
     viewMenu.addMenuListener(new MenuListener() {
+      @Override
       public void menuSelected(MenuEvent e) {
         viewMenu.removeAll();
         populateSkinMenu(viewMenu);
       }
+      @Override
       public void menuDeselected(MenuEvent e) {
       }
+      @Override
       public void menuCanceled(MenuEvent e) {
       }
     });
@@ -266,6 +269,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     this.setJMenuBar(menuBar);
 
     Action zoomInAction = new AbstractAction("Zoom in") {
+      @Override
       public void actionPerformed(ActionEvent e) {
         zoomToFactor(zoomFactor() * 1.2);
       }
@@ -278,6 +282,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     zoomMenu.add(zoomInItem);
 
     Action zoomOutAction = new AbstractAction("Zoom out") {
+      @Override
       public void actionPerformed(ActionEvent e) {
         zoomToFactor(zoomFactor() / 1.2);
       }
@@ -291,6 +296,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     JMenuItem resetViewportItem = new JMenuItem("Reset viewport");
     resetViewportItem.addActionListener(new ActionListener() {
+      @Override
       public void actionPerformed(ActionEvent e) {
         resetViewport = 1;
         repaint();
@@ -302,6 +308,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     /* Main canvas */
     canvas = new JPanel() {
       private static final long serialVersionUID = 1L;
+      @Override
       public void paintComponent(Graphics g) {
         super.paintComponent(g);
 
@@ -328,16 +335,19 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     /* Observe simulation and mote positions */
     posObserver = new Observer() {
+      @Override
       public void update(Observable obs, Object obj) {
         repaint();
       }
     };
     simulation.getEventCentral().addMoteCountListener(newMotesListener = new MoteCountListener() {
+      @Override
       public void moteWasAdded(Mote mote) {
         Position pos = mote.getInterfaces().getPosition();
         if (pos != null) {
           pos.addObserver(posObserver);
           SwingUtilities.invokeLater(new Runnable() {
+            @Override
             public void run() {
               resetViewport = 1;
               repaint();
@@ -345,6 +355,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
           });
         }
       }
+      @Override
       public void moteWasRemoved(Mote mote) {
         Position pos = mote.getInterfaces().getPosition();
         if (pos != null) {
@@ -362,6 +373,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     /* Observe mote highlights */
     gui.addMoteHighlightObserver(moteHighligtObserver = new Observer() {
+      @Override
       public void update(Observable obs, Object obj) {
         if (!(obj instanceof Mote)) {
           return;
@@ -370,6 +382,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
         final Timer timer = new Timer(100, null);
         final Mote mote = (Mote) obj;
         timer.addActionListener(new ActionListener() {
+          @Override
           public void actionPerformed(ActionEvent e) {
             /* Count down */
             if (timer.getDelay() < 90) {
@@ -395,6 +408,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     /* Observe mote relations */
     gui.addMoteRelationsObserver(moteRelationsObserver = new Observer() {
+      @Override
       public void update(Observable obs, Object obj) {
         repaint();
       }
@@ -408,6 +422,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
     });
     canvas.addMouseListener(new MouseAdapter() {
+      @Override
       public void mousePressed(MouseEvent e) {
         if (e.isPopupTrigger()) {
           handlePopupRequest(e.getPoint());
@@ -418,6 +433,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
           handleMousePress(e);
         }
       }
+      @Override
       public void mouseReleased(MouseEvent e) {
         if (e.isPopupTrigger()) {
           handlePopupRequest(e.getPoint());
@@ -430,6 +446,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
     });
     canvas.addMouseWheelListener(new MouseWheelListener() {
+      @Override
       public void mouseWheelMoved(MouseWheelEvent mwe) {
         int x = mwe.getX();
         int y = mwe.getY();
@@ -457,6 +474,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 
     /* Drag and drop files to motes */
     DropTargetListener dTargetListener = new DropTargetListener() {
+      @Override
       public void dragEnter(DropTargetDragEvent dtde) {
         if (acceptOrRejectDrag(dtde)) {
           dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
@@ -464,8 +482,10 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
           dtde.rejectDrag();
         }
       }
+      @Override
       public void dragExit(DropTargetEvent dte) {
       }
+      @Override
       public void dropActionChanged(DropTargetDragEvent dtde) {
         if (acceptOrRejectDrag(dtde)) {
           dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
@@ -473,6 +493,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
           dtde.rejectDrag();
         }
       }
+      @Override
       public void dragOver(DropTargetDragEvent dtde) {
         if (acceptOrRejectDrag(dtde)) {
           dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE);
@@ -480,6 +501,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
           dtde.rejectDrag();
         }
       }
+      @Override
       public void drop(DropTargetDropEvent dtde) {
         Transferable transferable = dtde.getTransferable();
 
@@ -589,6 +611,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     repaint();
   }
 
+  @Override
   public void startPlugin() {
     super.startPlugin();
     if (loadedConfig) {
@@ -677,6 +700,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
             if (menuAction.isEnabled(this, mote)) {
               JMenuItem menuItem = new JMenuItem(menuAction.getDescription(this, mote));
               menuItem.addActionListener(new ActionListener() {
+                @Override
                 public void actionPerformed(ActionEvent e) {
                   menuAction.doAction(Visualizer.this, mote);
                 }
@@ -700,6 +724,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
         if (menuAction.isEnabled(this, simulation)) {
           JMenuItem menuItem = new JMenuItem(menuAction.getDescription(this, simulation));
           menuItem.addActionListener(new ActionListener() {
+            @Override
             public void actionPerformed(ActionEvent e) {
               menuAction.doAction(Visualizer.this, simulation);
             }
@@ -735,6 +760,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
 	  /* Mote-to-mote relations */
 	  JCheckBoxMenuItem moteRelationsItem = new JCheckBoxMenuItem("Mote relations", showMoteToMoteRelations);
 	  moteRelationsItem.addItemListener(new ItemListener() {
+      @Override
 		  public void itemStateChanged(ItemEvent e) {
 			  JCheckBoxMenuItem menuItem = ((JCheckBoxMenuItem)e.getItem());
 			  showMoteToMoteRelations = menuItem.isSelected();
@@ -769,6 +795,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
 
       item.addItemListener(new ItemListener() {
+        @Override
         public void itemStateChanged(ItemEvent e) {
           JCheckBoxMenuItem menuItem = ((JCheckBoxMenuItem)e.getItem());
           if (menuItem == null) {
@@ -1248,6 +1275,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     /* Center visible motes */
     final double smallXfinal = smallX, bigXfinal = bigX, smallYfinal = smallY, bigYfinal = bigY;
     SwingUtilities.invokeLater(new Runnable() {
+      @Override
       public void run() {
         Position viewMid =
           transformPixelToPosition(canvas.getWidth()/2, canvas.getHeight()/2);
@@ -1331,6 +1359,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     return (y - viewportTransform.getTranslateY())/viewportTransform.getScaleY() ;
   }
 
+  @Override
   public void closePlugin() {
     for (VisualizerSkin skin: currentSkins) {
       skin.setInactive();
@@ -1367,6 +1396,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     return selectedMotes;
   }
 
+  @Override
   public Collection<Element> getConfigXML() {
     ArrayList<Element> config = new ArrayList<Element>();
     Element element;
@@ -1411,6 +1441,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     return config;
   }
 
+  @Override
   public boolean setConfigXML(Collection<Element> configXML, boolean visAvailable) {
     loadedConfig = true;
     showMoteToMoteRelations = false;
@@ -1429,6 +1460,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
               || wanted.equals(Cooja.getDescriptionOf(skinClass))) {
             final Class<? extends VisualizerSkin> skin = skinClass;
             SwingUtilities.invokeLater(new Runnable() {
+              @Override
               public void run() {
                 generateAndActivateSkin(skin);
               }
@@ -1467,6 +1499,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
   }
 
   private AbstractAction makeSkinsDefaultAction = new AbstractAction() {
+    @Override
     public void actionPerformed(ActionEvent e) {
       StringBuilder sb = new StringBuilder();
       for (VisualizerSkin skin: currentSkins) {
@@ -1480,37 +1513,46 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
   };
 
   protected static class ButtonClickMoteMenuAction implements MoteMenuAction {
+    @Override
     public boolean isEnabled(Visualizer visualizer, Mote mote) {
       return mote.getInterfaces().getButton() != null
       && !mote.getInterfaces().getButton().isPressed();
     }
+    @Override
     public String getDescription(Visualizer visualizer, Mote mote) {
       return "Click button on " + mote;
     }
+    @Override
     public void doAction(Visualizer visualizer, Mote mote) {
       mote.getInterfaces().getButton().clickButton();
     }
   };
 
   protected static class DeleteMoteMenuAction implements MoteMenuAction {
+    @Override
     public boolean isEnabled(Visualizer visualizer, Mote mote) {
       return true;
     }
+    @Override
     public String getDescription(Visualizer visualizer, Mote mote) {
       return "Delete " + mote;
     }
+    @Override
     public void doAction(Visualizer visualizer, Mote mote) {
       mote.getSimulation().removeMote(mote);
     }
   };
 
   protected static class ShowLEDMoteMenuAction implements MoteMenuAction {
+    @Override
     public boolean isEnabled(Visualizer visualizer, Mote mote) {
       return mote.getInterfaces().getLED() != null;
     }
+    @Override
     public String getDescription(Visualizer visualizer, Mote mote) {
       return "Show LEDs on " + mote;
     }
+    @Override
     public void doAction(Visualizer visualizer, Mote mote) {
       Simulation simulation = mote.getSimulation();
       LED led = mote.getInterfaces().getLED();
@@ -1536,6 +1578,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
   };
 
   protected static class ShowSerialMoteMenuAction implements MoteMenuAction {
+    @Override
     public boolean isEnabled(Visualizer visualizer, Mote mote) {
       for (MoteInterface intf: mote.getInterfaces().getInterfaces()) {
         if (intf instanceof SerialPort) {
@@ -1544,9 +1587,11 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
       return false;
     }
+    @Override
     public String getDescription(Visualizer visualizer, Mote mote) {
       return "Show serial port on " + mote;
     }
+    @Override
     public void doAction(Visualizer visualizer, Mote mote) {
       Simulation simulation = mote.getSimulation();
       SerialPort serialPort = null;
@@ -1579,31 +1624,38 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
   };
 
   protected static class MoveMoteMenuAction implements MoteMenuAction {
+    @Override
     public boolean isEnabled(Visualizer visualizer, Mote mote) {
       return true;
     }
+    @Override
     public String getDescription(Visualizer visualizer, Mote mote) {
       return "Move " + mote;
     }
+    @Override
     public void doAction(Visualizer visualizer, Mote mote) {
       visualizer.beginMoveRequest(mote, false, false);
     }
   };
 
   protected static class ResetViewportAction implements SimulationMenuAction {
+    @Override
     public void doAction(Visualizer visualizer, Simulation simulation) {
       visualizer.resetViewport = 1;
       visualizer.repaint();
     }
+    @Override
     public String getDescription(Visualizer visualizer, Simulation simulation) {
       return "Reset viewport";
     }
+    @Override
     public boolean isEnabled(Visualizer visualizer, Simulation simulation) {
       return true;
     }
   };
 
   protected static class ToggleDecorationsMenuAction implements SimulationMenuAction {
+    @Override
     public void doAction(final Visualizer visualizer, Simulation simulation) {
       if (!(visualizer.getUI() instanceof BasicInternalFrameUI)) {
         return;
@@ -1620,11 +1672,13 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
       visualizer.revalidate();
       SwingUtilities.invokeLater(new Runnable() {
+        @Override
         public void run() {
           visualizer.repaint();
         }
       });
     }
+    @Override
     public String getDescription(Visualizer visualizer, Simulation simulation) {
       if (!(visualizer.getUI() instanceof BasicInternalFrameUI)) {
         return "Hide window decorations";
@@ -1637,6 +1691,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
       }
       return "Hide window decorations";
     }
+    @Override
     public boolean isEnabled(Visualizer visualizer, Simulation simulation) {
       if (!(visualizer.getUI() instanceof BasicInternalFrameUI)) {
         return false;
@@ -1645,6 +1700,7 @@ public class Visualizer extends VisPlugin implements HasQuickHelp {
     }
   }
 
+  @Override
   public String getQuickHelp() {
     return "<b>Network</b> "
             + "<p>The network window shows the positions of simulated motes. "
diff --git a/tools/cooja/java/org/contikios/cooja/plugins/skins/DGRMVisualizerSkin.java b/tools/cooja/java/org/contikios/cooja/plugins/skins/DGRMVisualizerSkin.java
index 76ed04ba7..ef8c19435 100644
--- a/tools/cooja/java/org/contikios/cooja/plugins/skins/DGRMVisualizerSkin.java
+++ b/tools/cooja/java/org/contikios/cooja/plugins/skins/DGRMVisualizerSkin.java
@@ -58,6 +58,7 @@ public class DGRMVisualizerSkin implements VisualizerSkin {
 	private Simulation simulation = null;
 	private Visualizer visualizer = null;
 
+  @Override
 	public void setActive(Simulation simulation, Visualizer vis) {
 		if (!(simulation.getRadioMedium() instanceof DirectedGraphMedium)) {
 			logger.fatal("Cannot activate DGRM skin for unknown radio medium: " + simulation.getRadioMedium());
@@ -67,6 +68,7 @@ public class DGRMVisualizerSkin implements VisualizerSkin {
 		this.visualizer = vis;
 	}
 
+  @Override
 	public void setInactive() {
 		if (simulation == null) {
 			/* Skin was never activated */
@@ -74,6 +76,7 @@ public class DGRMVisualizerSkin implements VisualizerSkin {
 		}
 	}
 
+  @Override
 	public Color[] getColorOf(Mote mote) {
 	  if (visualizer.getSelectedMotes().contains(mote)) {
 	    return new Color[] { Color.CYAN };
@@ -81,6 +84,7 @@ public class DGRMVisualizerSkin implements VisualizerSkin {
 	  return null;
 	}
 
+  @Override
 	public void paintBeforeMotes(Graphics g) {
 		Set<Mote> selectedMotes = visualizer.getSelectedMotes();
 		if (simulation == null || selectedMotes == null) {
@@ -150,9 +154,11 @@ public class DGRMVisualizerSkin implements VisualizerSkin {
 		}
 	}
 
+  @Override
 	public void paintAfterMotes(Graphics g) {
 	}
 
+  @Override
 	public Visualizer getVisualizer() {
 		return visualizer;
 	}