Bug 309041 -  [compatibility] NPE importing preferences

bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/PlatformUIPreferenceListener.java

diff --git a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/PlatformUIPreferenceListener.java b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/PlatformUIPreferenceListener.java
index 0a2eb55..3d9455a 100644
--- a/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/PlatformUIPreferenceListener.java
+++ b/bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/PlatformUIPreferenceListener.java
@@ -152,7 +152,7 @@
 						for (int j = 0; j < maps.length; j++) {
 							IFileEditorMapping fileEditorMapping = maps[j];
 							IEditorDescriptor descriptor = fileEditorMapping.getDefaultEditor();
-							if (!editorMap.containsKey(descriptor.getId())) {
+							if (descriptor != null && !editorMap.containsKey(descriptor.getId())) {
 								editorMap.put(descriptor.getId(), descriptor);
 							}
 						}