diff --git a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/themes/CascadingTheme.java b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/themes/CascadingTheme.java
index a7bd34e6a9c..4eeb85dcb26 100755
--- a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/themes/CascadingTheme.java	
+++ b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/themes/CascadingTheme.java	
@@ -102,7 +102,7 @@ public boolean getBoolean(String key) {
 	}
 
 	@Override
-	public Set keySet() {
+	public Set<String> keySet() {
 		return currentTheme.keySet();
 	}