diff --git a/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java b/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java
index f1714ea39c99a7091140cfea1ed88fadb5b5c579..60d989654fe8deccfa77397b832e232efd9e0958 100644
--- a/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java
+++ b/src/share/classes/sun/nio/cs/AbstractCharsetProvider.java
@@ -179,7 +179,9 @@ public class AbstractCharsetProvider
 
                 public Charset next() {
                     String csn = i.next();
-                    return lookup(csn);
+                    synchronized (AbstractCharsetProvider.this) {
+                        return lookup(csn);
+                    }
                 }
 
                 public void remove() {