diff --git a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/DerivedStateAwareResource.java b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/DerivedStateAwareResource.java
index e641dd242..9be171324 100644
--- a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/DerivedStateAwareResource.java
+++ b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/DerivedStateAwareResource.java
@@ -53,6 +53,9 @@ public class DerivedStateAwareResource extends LazyLinkingResource {
 		return super.getContents();
 	}
 	
+	/**
+	 * @since 2.4
+	 */
 	@Override
 	protected void clearInternalState() {
 		if (fullyInitialized) {