--- old/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java	2011-09-01 11:36:19.000000000 -0700
+++ new/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java	2011-09-01 11:36:18.000000000 -0700
@@ -179,7 +179,9 @@
 
                 public Charset next() {
                     String csn = i.next();
-                    return lookup(csn);
+                    synchronized (AbstractCharsetProvider.this) {
+                        return lookup(csn);
+                    }
                 }
 
                 public void remove() {