diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/OSGiPreferencesServiceImpl.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/OSGiPreferencesServiceImpl.java
index 14982e0712e..7b3055ee05c 100644
--- a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/OSGiPreferencesServiceImpl.java
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/internal/preferences/OSGiPreferencesServiceImpl.java
@@ -38,10 +38,10 @@ public class OSGiPreferencesServiceImpl implements PreferencesService {
 	private static final class OSGiLocalRootPreferences implements Preferences {
 
 		// The "local" root of this preference tree (not the real Eclipse root)
-		private Preferences root;
+		private final Preferences root;
 
 		// the node this node is wrappering
-		private Preferences wrapped;
+		private final Preferences wrapped;
 
 		private OSGiLocalRootPreferences(Preferences root) {
 			this(root, root);
@@ -252,7 +252,7 @@ public void sync() throws BackingStoreException {
 
 	} // end static inner class OSGiLocalRootPreferences
 
-	private IEclipsePreferences bundlePreferences;
+	private final IEclipsePreferences bundlePreferences;
 
 	OSGiPreferencesServiceImpl(IEclipsePreferences bundlePreferences) {
 		this.bundlePreferences = bundlePreferences;
diff --git a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/IEclipsePreferences.java b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/IEclipsePreferences.java
index 735f9c03af1..e46847e6e0a 100644
--- a/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/IEclipsePreferences.java
+++ b/bundles/org.eclipse.equinox.preferences/src/org/eclipse/core/runtime/preferences/IEclipsePreferences.java
@@ -42,7 +42,7 @@ public final class NodeChangeEvent extends EventObject {
 		 */
 		private static final long serialVersionUID = 1L;
 
-		private Preferences child;
+		private final Preferences child;
 
 		/**
 		 * Constructor for a new node change event object.
@@ -127,9 +127,9 @@ public final class PreferenceChangeEvent extends EventObject {
 		 */
 		private static final long serialVersionUID = 1L;
 
-		private String key;
-		private Object newValue;
-		private Object oldValue;
+		private final String key;
+		private final Object newValue;
+		private final Object oldValue;
 
 		/**
 		 * Constructor for a new preference change event. The node and the key must not