8077418: StackOverflowError during PolicyFile lookup

Reviewed-by: mullan

src/share/classes/java/security/ProtectionDomain.java

 /*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, 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
@@ -25,7 +25,6 @@
 
 package java.security;
 
-import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Enumeration;
@@ -457,37 +456,24 @@ public class ProtectionDomain {
     /**
      * Used for storing ProtectionDomains as keys in a Map.
      */
-    final static class Key {}
-
-    // A cache of ProtectionDomains and their Permissions
-    private static class PDCache implements ProtectionDomainCache {
-        // We must wrap the PermissionCollection in a WeakReference as there
-        // are some PermissionCollections which contain strong references
-        // back to a ProtectionDomain and otherwise would never be removed
-        // from the WeakHashMap
-        private final Map<Key, WeakReference<PermissionCollection>>
-            map = new WeakHashMap<>();
-
-        @Override
-        public synchronized void put(ProtectionDomain pd,
-                                     PermissionCollection pc) {
-            map.put(pd == null ? null : pd.key, new WeakReference<>(pc));
-        }
-
-        @Override
-        public synchronized PermissionCollection get(ProtectionDomain pd) {
-            WeakReference<PermissionCollection> ref =
-                map.get(pd == null ? null : pd.key);
-            return ref == null ? null : ref.get();
-        }
-    }
+    final class Key {}
 
     static {
         SharedSecrets.setJavaSecurityProtectionDomainAccess(
             new JavaSecurityProtectionDomainAccess() {
-                @Override
                 public ProtectionDomainCache getProtectionDomainCache() {
-                    return new PDCache();
+                    return new ProtectionDomainCache() {
+                        private final Map<Key, PermissionCollection> map =
+                            Collections.synchronizedMap
+                                (new WeakHashMap<Key, PermissionCollection>());
+                        public void put(ProtectionDomain pd,
+                            PermissionCollection pc) {
+                            map.put((pd == null ? null : pd.key), pc);
+                        }
+                        public PermissionCollection get(ProtectionDomain pd) {
+                            return pd == null ? map.get(null) : map.get(pd.key);
+                        }
+                    };
                 }
             });
     }