diff -r 400a4e8accd3 -r bdcef2ef52d2 src/share/classes/com/sun/tools/javac/nio/JavacPathFileManager.java
--- a/src/share/classes/com/sun/tools/javac/nio/JavacPathFileManager.java	Thu Nov 15 19:54:20 2012 -0800
+++ b/src/share/classes/com/sun/tools/javac/nio/JavacPathFileManager.java	Thu Nov 15 23:07:24 2012 -0800
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -253,7 +253,8 @@
             for (File f: files)
                 pl.add(f.toPath());
         }
-        pathsForLocation.put(locn, pl);
+        if (!pl.isEmpty())
+            pathsForLocation.put(locn, pl);
     }
 
     private void lazyInitSearchPaths() {
@@ -513,7 +514,8 @@
     }
 
     private static String getRelativePath(String packageName, String relativeName) {
-        return packageName.replace(".", "/") + relativeName;
+        return packageName.isEmpty()
+                ? relativeName : packageName.replace(".", "/") + "/" + relativeName;
     }
 
     private static String getBaseName(String relativePath) {