### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/internal/core/JavaProjectElementInfo.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/JavaProjectElementInfo.java,v
retrieving revision 1.47
diff -u -r1.47 JavaProjectElementInfo.java
--- model/org/eclipse/jdt/internal/core/JavaProjectElementInfo.java	24 Apr 2007 11:17:09 -0000	1.47
+++ model/org/eclipse/jdt/internal/core/JavaProjectElementInfo.java	26 Apr 2007 08:47:48 -0000
@@ -308,6 +308,10 @@
 					}
 					fragmentsCache = (HashSetOfArray) rootProjectCache.pkgFragmentsCaches.get(root);
 				}
+				if (fragmentsCache == null) { // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=183833
+					fragmentsCache = new HashSetOfArray();
+					initializePackageNames(root, fragmentsCache);
+				}
 				Object[][] set = fragmentsCache.set;
 				for (int j = 0, length2 = set.length; j < length2; j++) {
 					String[] pkgName = (String[]) set[j];