diff --git a/libgrowl/src/java/info/growl/GrowlNative.java b/libgrowl/src/java/info/growl/GrowlNative.java
index 65a18e84..482f15d2 100644
--- a/libgrowl/src/java/info/growl/GrowlNative.java
+++ b/libgrowl/src/java/info/growl/GrowlNative.java
@@ -37,175 +37,144 @@ import javax.imageio.ImageIO;
 
 /**
  * Growl notification implementation. This uses JNI to send messages to Growl.
- * 
+ *
  * @author Michael Stringer
  * @version 0.1
  */
 class GrowlNative implements Growl {
-    private String appName;
-    private List<NotificationType> notifications;
-    private List<GrowlCallbackListener> callbackListeners;
+    private final String appName;
+    private final List<NotificationType> notifications;
+    private final List<GrowlCallbackListener> callbackListeners;
     private byte[] imageData;
 
     private native void sendNotification(String appName, String name,
-	    String title, String message, String callbackContext, byte[] icon);
+                                         String title, String message, String callbackContext, byte[] icon);
 
     private native void registerApp(String appName, byte[] image,
-	    List<NotificationType> notifications);
+                                    List<NotificationType> notifications);
 
     /**
      * Creates a new <code>GrowlNative</code> instance for the specified
      * application name.
-     * 
-     * @param appName
-     *                The name of the application sending notifications.
+     *
+     * @param appName The name of the application sending notifications.
      */
     GrowlNative(String appName) {
-	notifications = new ArrayList<NotificationType>();
-	callbackListeners = new ArrayList<GrowlCallbackListener>();
-	this.appName = appName;
+        notifications = new ArrayList<NotificationType>();
+        callbackListeners = new ArrayList<GrowlCallbackListener>();
+        this.appName = appName;
     }
 
+    @SuppressWarnings({"UnusedDeclaration"})
     void fireCallbacks(String callbackContext) {
-	for (GrowlCallbackListener listener : callbackListeners) {
-	    listener.notificationWasClicked(callbackContext);
-	}
+        for (GrowlCallbackListener listener : callbackListeners) {
+            listener.notificationWasClicked(callbackContext);
+        }
     }
 
     /**
      * {@inheritDoc}
      */
     public void register() throws GrowlException {
-	registerApp(appName, imageData, notifications);
+        registerApp(appName, imageData, notifications);
     }
 
     /**
      * {@inheritDoc}
      */
     public void addNotification(String name, boolean enabledByDefault) {
-	notifications.add(new NotificationType(name, enabledByDefault));
+        notifications.add(new NotificationType(name, enabledByDefault));
     }
 
     /**
      * {@inheritDoc}
      */
     public void addCallbackListener(GrowlCallbackListener listener) {
-	callbackListeners.add(listener);
+        callbackListeners.add(listener);
     }
 
     /**
      * {@inheritDoc}
      */
     public void setIcon(RenderedImage icon) throws GrowlException {
-	try {
-	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
-	    ImageIO.write(icon, "png", baos);
+        imageData = convertImage(icon);
+    }
 
-	    imageData = baos.toByteArray();
-	} catch (IOException e) {
-	    // TODO Auto-generated catch block
-	    e.printStackTrace();
-	}
+    protected byte[] convertImage(RenderedImage icon) throws GrowlException {
+        if (icon == null) {
+            return null;
+        }
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        try {
+            ImageIO.write(icon, "png", baos);
+        } catch (IOException ioe) {
+            throw new GrowlException("Failed to convert Image", ioe);
+        }
+        return baos.toByteArray();
     }
 
     /**
      * {@inheritDoc}
      */
     public void sendNotification(String name, String title, String body)
-	    throws GrowlException {
-	if (!notifications.contains(new NotificationType(name, false))) {
-	    System.out.println("contains: " + notifications);
-	    throw new GrowlException("Unregistered notification name [" + name
-		    + "]");
-	}
-	sendNotification(appName, name, title, body, null, null);
+            throws GrowlException {
+        sendNotification(name, title, body, null, null);
     }
 
     /**
      * {@inheritDoc}
      */
-    public void sendNotification(String name, String title, String body,
-	    RenderedImage icon) throws GrowlException {
-	if (!notifications.contains(new NotificationType(name, false))) {
-	    System.out.println("contains: " + notifications);
-	    throw new GrowlException("Unregistered notification name [" + name
-		    + "]");
-	}
-
-	try {
-	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
-	    ImageIO.write(icon, "png", baos);
-
-	    byte[] image = baos.toByteArray();
-
-	    sendNotification(appName, name, title, body, null, image);
-	} catch (IOException ioe) {
-	    throw new GrowlException("Failed to convert Image", ioe);
-	}
+    public void sendNotification(String name, String title, String body, RenderedImage icon) throws GrowlException {
+        sendNotification(name, title, body, null, icon);
     }
 
     /**
      * {@inheritDoc}
      */
-    public void sendNotification(String name, String title, String body,
-	    String callbackContext) throws GrowlException {
-	if (!notifications.contains(new NotificationType(name, false))) {
-	    System.out.println("contains: " + notifications);
-	    throw new GrowlException("Unregistered notification name [" + name
-		    + "]");
-	}
-
-	sendNotification(appName, name, title, body, callbackContext, null);
+    public void sendNotification(String name, String title, String body, String callbackContext) throws GrowlException {
+        sendNotification(name, title, body, callbackContext, null);
     }
 
     /**
      * {@inheritDoc}
      */
-    public void sendNotification(String name, String title, String body,
-	    String callbackContext, RenderedImage icon) throws GrowlException {
-	if (!notifications.contains(new NotificationType(name, false))) {
-	    System.out.println("contains: " + notifications);
-	    throw new GrowlException("Unregistered notification name [" + name
-		    + "]");
-	}
+    public void sendNotification(String name, String title, String body, String callbackContext, RenderedImage icon)
+            throws GrowlException {
+        if (!notifications.contains(new NotificationType(name, false))) {
+            throw new GrowlException("Unregistered notification name [" + name + ']');
+        }
 
-	try {
-	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
-	    ImageIO.write(icon, "png", baos);
-
-	    byte[] image = baos.toByteArray();
-
-	    sendNotification(appName, name, title, body, callbackContext, image);
-	} catch (IOException ioe) {
-	    throw new GrowlException("Failed to convert Image", ioe);
-	}
+        sendNotification(appName, name, title, body, callbackContext, convertImage(icon));
     }
 
     private class NotificationType {
-	private String name;
-	private boolean enabledByDefault;
+        private final String name;
+        private final boolean enabledByDefault;
 
-	public NotificationType(String name, boolean enabledByDefault) {
-	    this.name = name;
-	    this.enabledByDefault = enabledByDefault;
-	}
+        private NotificationType(String name, boolean enabledByDefault) {
+            this.name = name;
+            this.enabledByDefault = enabledByDefault;
+        }
 
-	public String getName() {
-	    return name;
-	}
+        @SuppressWarnings({"UnusedDeclaration"})
+        public String getName() {
+            return name;
+        }
 
-	public boolean isEnabledByDefault() {
-	    return enabledByDefault;
-	}
+        @SuppressWarnings({"UnusedDeclaration"})
+        public boolean isEnabledByDefault() {
+            return enabledByDefault;
+        }
 
-	public boolean equals(Object other) {
-	    if (!(other instanceof NotificationType)) {
-		return false;
-	    }
+        @Override
+        public boolean equals(Object other) {
+            return (other instanceof NotificationType) &&
+                    name.equals(((NotificationType) other).name);
+        }
 
-	    NotificationType otherType = (NotificationType) other;
-
-	    return name.equals(otherType.name);
-	}
+        @Override
+        public int hashCode() {
+            return name.hashCode();
+        }
     }
 }
diff --git a/libgrowl/src/java/info/growl/GrowlUtils.java b/libgrowl/src/java/info/growl/GrowlUtils.java
index 916d5daa..1958de0b 100644
--- a/libgrowl/src/java/info/growl/GrowlUtils.java
+++ b/libgrowl/src/java/info/growl/GrowlUtils.java
@@ -32,65 +32,65 @@ import java.util.Map;
 
 /**
  * Utility class for sending notifications using Growl.
- * 
+ *
  * @author Michael Stringer
  * @version 0.1
  */
 public final class GrowlUtils {
     private static final boolean GROWL_LOADED;
-    private static Map<String, Growl> instances = new HashMap<String, Growl>();
+    private static final Map<String, Growl> instances = new HashMap<String, Growl>();
 
     static {
-	boolean loaded = false;
-	try {
-	    System.loadLibrary("growl");
-	    loaded = true;
-	} catch (UnsatisfiedLinkError ule) {
-	    System.out.println("Failed to load Growl library");
-	}
+        boolean loaded = false;
+        try {
+            System.loadLibrary("growl");
+            loaded = true;
+        } catch (UnsatisfiedLinkError ule) {
+            // ignore: growl not available
+        }
 
-	GROWL_LOADED = loaded;
+        GROWL_LOADED = loaded;
     }
 
     /**
      * Utility method - should not be instantiated.
      */
     private GrowlUtils() {
-
     }
 
     /**
      * Gets a <code>Growl</code> instance to use for the specified application
      * name. Multiple calls to this method will return the same instance.
-     * 
-     * @param appName
-     *                The name of the application.
+     *
+     * @param appName The name of the application.
      * @return The <code>Growl</code> instance to use.
      */
     public static Growl getGrowlInstance(String appName) {
-	Growl instance = instances.get(appName);
+        synchronized (instances) {
+            Growl instance = instances.get(appName);
 
-	if (instance == null) {
-	    if (GROWL_LOADED) {
-		instance = new GrowlNative(appName);
-	    } else {
-		instance = new DummyGrowl();
-	    }
+            if (instance == null) {
+                if (GROWL_LOADED) {
+                    instance = new GrowlNative(appName);
+                } else {
+                    instance = new DummyGrowl();
+                }
 
-	    instances.put(appName, instance);
-	}
+                instances.put(appName, instance);
+            }
 
-	return instance;
+            return instance;
+        }
     }
 
     /**
      * Gets whether messages can be sent to Growl. If this returns
      * <code>false</code> then {@link #getGrowlInstance(String)} will return a
      * dummy object.
-     * 
+     *
      * @return <code>true</code> if messages can be sent to Growl.
      */
     public static boolean isGrowlLoaded() {
-	return GROWL_LOADED;
+        return GROWL_LOADED;
     }
 }
diff --git a/libgrowl/src/java/info/growl/test/TestGrowl.java b/libgrowl/src/java/info/growl/test/TestGrowl.java
index e570279a..c6af0040 100644
--- a/libgrowl/src/java/info/growl/test/TestGrowl.java
+++ b/libgrowl/src/java/info/growl/test/TestGrowl.java
@@ -47,7 +47,7 @@ import javax.swing.SwingUtilities;
 
 /**
  * Simple test class for Growl.
- * 
+ *
  * @author Michael Stringer
  * @version 0.1
  */
@@ -55,132 +55,138 @@ public class TestGrowl extends JFrame {
     private static final String APP_NAME = "Test Java App";
     private static final String NOTIF_3_CALLBACK = "Notif3";
 
+    /**
+     * Test Growl.
+     */
     public TestGrowl() {
-	super("Growl for Java");
-	setSize(320, 290);
+        super("Growl for Java");
+        setSize(320, 290);
 
-	buildComponents();
-	setVisible(true);
-	setDefaultCloseOperation(EXIT_ON_CLOSE);
+        buildComponents();
+        setVisible(true);
+        setDefaultCloseOperation(EXIT_ON_CLOSE);
     }
 
     private void buildComponents() {
-	getContentPane().setLayout(new GridLayout(6, 1));
+        getContentPane().setLayout(new GridLayout(6, 1));
 
-	Action action = new AbstractAction("Register") {
-	    public void actionPerformed(ActionEvent ae) {
-		try {
-		    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
+        Action action = new AbstractAction("Register") {
+            public void actionPerformed(ActionEvent ae) {
+                try {
+                    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
 
-		    growl.addNotification("Test Notification 1", true);
-		    growl.addNotification("Test Notification 2", false);
-		    growl.addNotification("Test Notification 3", true);
+                    growl.addNotification("Test Notification 1", true);
+                    growl.addNotification("Test Notification 2", false);
+                    growl.addNotification("Test Notification 3", true);
 
-		    GrowlCallbackListener listener = new GrowlCallbackListener() {
-			public void notificationWasClicked(
-				final String clickContext) {
-			    SwingUtilities.invokeLater(new Runnable() {
-				public void run() {
-				    if (NOTIF_3_CALLBACK.equals(clickContext)) {
-					JOptionPane
-						.showMessageDialog(
-							TestGrowl.this,
-							"User clicked on 'Test Notification 3'");
-				    }
-				}
-			    });
-			}
-		    };
+                    GrowlCallbackListener listener = new GrowlCallbackListener() {
+                        public void notificationWasClicked(
+                                final String clickContext) {
+                            SwingUtilities.invokeLater(new Runnable() {
+                                public void run() {
+                                    if (NOTIF_3_CALLBACK.equals(clickContext)) {
+                                        JOptionPane
+                                                .showMessageDialog(
+                                                        TestGrowl.this,
+                                                        "User clicked on 'Test Notification 3'");
+                                    }
+                                }
+                            });
+                        }
+                    };
 
-		    growl.addCallbackListener(listener);
-		    growl.register();
-		} catch (GrowlException ge) {
-		    ge.printStackTrace();
-		}
-	    }
-	};
+                    growl.addCallbackListener(listener);
+                    growl.register();
+                } catch (GrowlException ge) {
+                    ge.printStackTrace();
+                }
+            }
+        };
 
-	getContentPane().add(new JButton(action));
+        getContentPane().add(new JButton(action));
 
-	action = new AbstractAction("Send 'Test Notification 1'") {
-	    public void actionPerformed(ActionEvent ae) {
-		try {
-		    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
+        action = new AbstractAction("Send 'Test Notification 1'") {
+            public void actionPerformed(ActionEvent ae) {
+                try {
+                    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
 
-		    growl.sendNotification("Test Notification 1",
-			    "Test Notif 1", "This is a test");
-		} catch (GrowlException ge) {
-		    ge.printStackTrace();
-		}
-	    }
-	};
-	getContentPane().add(new JButton(action));
+                    growl.sendNotification("Test Notification 1",
+                            "Test Notif 1", "This is a test");
+                } catch (GrowlException ge) {
+                    ge.printStackTrace();
+                }
+            }
+        };
+        getContentPane().add(new JButton(action));
 
-	action = new AbstractAction("Send 'Test Notification 2'") {
-	    public void actionPerformed(ActionEvent ae) {
-		try {
-		    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
-		    BufferedImage image = ImageIO.read(TestGrowl.class
-			    .getResource("/images/duke.gif"));
-		    growl.sendNotification("Test Notification 2",
-			    "Test Notif 2", "This is another test", image);
-		} catch (GrowlException ge) {
-		    ge.printStackTrace();
-		} catch (IOException e) {
-		    // TODO Auto-generated catch block
-		    e.printStackTrace();
-		}
-	    }
-	};
-	getContentPane().add(new JButton(action));
+        action = new AbstractAction("Send 'Test Notification 2'") {
+            public void actionPerformed(ActionEvent ae) {
+                try {
+                    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
+                    BufferedImage image = ImageIO.read(TestGrowl.class
+                            .getResource("/images/duke.gif"));
+                    growl.sendNotification("Test Notification 2",
+                            "Test Notif 2", "This is another test", image);
+                } catch (GrowlException ge) {
+                    ge.printStackTrace();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        };
+        getContentPane().add(new JButton(action));
 
-	action = new AbstractAction("Test Callback 'Notification 3'") {
-	    public void actionPerformed(ActionEvent ae) {
-		try {
-		    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
+        action = new AbstractAction("Test Callback 'Notification 3'") {
+            public void actionPerformed(ActionEvent ae) {
+                try {
+                    Growl growl = GrowlUtils.getGrowlInstance(APP_NAME);
 
-		    growl.sendNotification("Test Notification 3",
-			    "Callback Test", "Click me - I dares you!", NOTIF_3_CALLBACK);
-		} catch (GrowlException ge) {
-		    ge.printStackTrace();
-		}
-	    }
-	};
-	getContentPane().add(new JButton(action));
+                    growl.sendNotification("Test Notification 3",
+                            "Callback Test", "Click me - I dares you!", NOTIF_3_CALLBACK);
+                } catch (GrowlException ge) {
+                    ge.printStackTrace();
+                }
+            }
+        };
+        getContentPane().add(new JButton(action));
 
-	action = new AbstractAction("Reg & Test App 2") {
-	    public void actionPerformed(ActionEvent ae) {
-		try {
-		    Growl growl = GrowlUtils.getGrowlInstance("Other App");
+        action = new AbstractAction("Reg & Test App 2") {
+            public void actionPerformed(ActionEvent ae) {
+                try {
+                    Growl growl = GrowlUtils.getGrowlInstance("Other App");
 
-		    growl.addNotification("A Notification", true);
+                    growl.addNotification("A Notification", true);
 
-		    BufferedImage image = ImageIO.read(TestGrowl.class
-			    .getResource("/images/duke.gif"));
-		    growl.setIcon(image);
+                    BufferedImage image = ImageIO.read(TestGrowl.class
+                            .getResource("/images/duke.gif"));
+                    growl.setIcon(image);
 
-		    growl.register();
-		    growl.sendNotification("A Notification", "Testin",
-			    "Blah de blah blah");
-		} catch (GrowlException ge) {
-		    ge.printStackTrace();
-		} catch (IOException e) {
-		    // TODO Auto-generated catch block
-		    e.printStackTrace();
-		}
-	    }
-	};
-	getContentPane().add(new JButton(action));
+                    growl.register();
+                    growl.sendNotification("A Notification", "Testin",
+                            "Blah de blah blah");
+                } catch (GrowlException ge) {
+                    ge.printStackTrace();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        };
+        getContentPane().add(new JButton(action));
 
-	action = new AbstractAction("Exit") {
-	    public void actionPerformed(ActionEvent ae) {
-		System.exit(0);
-	    }
-	};
-	getContentPane().add(new JButton(action));
+        action = new AbstractAction("Exit") {
+            public void actionPerformed(ActionEvent ae) {
+                System.exit(0);
+            }
+        };
+        getContentPane().add(new JButton(action));
     }
 
-    public static final void main(String[] args) {
-	new TestGrowl();
+    /**
+     * Test growl.
+     * @param args args
+     */
+    public static void main(String[] args) {
+        //noinspection ResultOfObjectAllocationIgnored
+        new TestGrowl();
     }
 }