diff -r b549c5ea34ab -r 2fcd3ddb57a6 src/share/jaf_classes/javax/activation/FileTypeMap.java
--- a/src/share/jaf_classes/javax/activation/FileTypeMap.java	Fri Dec 13 17:20:01 2013 -0800
+++ b/src/share/jaf_classes/javax/activation/FileTypeMap.java	Sun Dec 15 23:35:45 2013 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2005, 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
@@ -26,6 +26,8 @@
 package javax.activation;
 
 import java.io.File;
+import java.util.Map;
+import java.util.WeakHashMap;
 
 /**
  * The FileTypeMap is an abstract class that provides a data typing
@@ -48,6 +50,8 @@
 public abstract class FileTypeMap {
 
     private static FileTypeMap defaultMap = null;
+    private static Map<ClassLoader,FileTypeMap> map =
+                                new WeakHashMap<ClassLoader,FileTypeMap>();
 
     /**
      * The default constructor.
@@ -78,11 +82,11 @@
      * Sets the default FileTypeMap for the system. This instance
      * will be returned to callers of getDefaultFileTypeMap.
      *
-     * @param map The FileTypeMap.
+     * @param fileTypeMap The FileTypeMap.
      * @exception SecurityException if the caller doesn't have permission
      *                                  to change the default
      */
-    public static void setDefaultFileTypeMap(FileTypeMap map) {
+    public static synchronized void setDefaultFileTypeMap(FileTypeMap fileTypeMap) {
         SecurityManager security = System.getSecurityManager();
         if (security != null) {
             try {
@@ -90,14 +94,17 @@
                 security.checkSetFactory();
             } catch (SecurityException ex) {
                 // otherwise, we also allow it if this code and the
-                // factory come from the same class loader (e.g.,
+                // factory come from the same (non-system) class loader (e.g.,
                 // the JAF classes were loaded with the applet classes).
-                if (FileTypeMap.class.getClassLoader() !=
-                        map.getClass().getClassLoader())
+                if (FileTypeMap.class.getClassLoader() == null ||
+                    FileTypeMap.class.getClassLoader() !=
+                        fileTypeMap.getClass().getClassLoader())
                     throw ex;
             }
         }
-        defaultMap = map;
+        // remove any per-thread-context-class-loader FileTypeMap
+        map.remove(SecuritySupport.getContextClassLoader());
+        defaultMap = fileTypeMap;
     }
 
     /**
@@ -109,10 +116,17 @@
      * @return The default FileTypeMap
      * @see javax.activation.FileTypeMap#setDefaultFileTypeMap
      */
-    public static FileTypeMap getDefaultFileTypeMap() {
-        // XXX - probably should be synchronized
-        if (defaultMap == null)
-            defaultMap = new MimetypesFileTypeMap();
-        return defaultMap;
+    public static synchronized FileTypeMap getDefaultFileTypeMap() {
+        if (defaultMap != null)
+            return defaultMap;
+
+        // fetch per-thread-context-class-loader default
+        ClassLoader tccl = SecuritySupport.getContextClassLoader();
+        FileTypeMap def = map.get(tccl);
+        if (def == null) {
+            def = new MimetypesFileTypeMap();
+            map.put(tccl, def);
+        }
+        return def;
     }
 }