string externalization
diff --git a/plugins/org.eclipse.graphiti/src/org/eclipse/graphiti/features/impl/AbstractFeatureProvider.java b/plugins/org.eclipse.graphiti/src/org/eclipse/graphiti/features/impl/AbstractFeatureProvider.java
index 3482f35..e724abb 100644
--- a/plugins/org.eclipse.graphiti/src/org/eclipse/graphiti/features/impl/AbstractFeatureProvider.java
+++ b/plugins/org.eclipse.graphiti/src/org/eclipse/graphiti/features/impl/AbstractFeatureProvider.java
@@ -667,9 +667,9 @@
 					for (int i = 0; i < businessObjects.length; i++) {
 						EObject bo = (EObject) businessObjects[i];
 						Resource resource = bo.eResource();
-						Assert.isNotNull(resource, " Business object " + bo + " is not contained in a resource"); //$NON-NLS-1$
+						Assert.isNotNull(resource, " Business object " + bo + " is not contained in a resource"); //$NON-NLS-1$ //$NON-NLS-2$
 						ResourceSet resourceSet = resource.getResourceSet();
-						Assert.isNotNull(resourceSet, " Resource " + resource + " is not contained in a resource set"); //$NON-NLS-1$
+						Assert.isNotNull(resourceSet, " Resource " + resource + " is not contained in a resource set"); //$NON-NLS-1$ //$NON-NLS-2$
 						TransactionalEditingDomain editingDomain = getDiagramTypeProvider().getDiagramEditor().getEditingDomain();
 						ResourceSet editorResourceSet = editingDomain.getResourceSet();
 						if (!resourceSet.equals(editorResourceSet)) {