src/share/classes/java/lang/Thread.java

@@ -143,11 +143,11 @@
     private static native void registerNatives();
     static {
         registerNatives();
     }
 
-    private char        name[];
+    private volatile char  name[];
     private int         priority;
     private Thread      threadQ;
     private long        eetop;
 
     /* Whether or not to single_step this thread. */

@@ -1133,11 +1133,11 @@
      * @exception  SecurityException  if the current thread cannot modify this
      *               thread.
      * @see        #getName
      * @see        #checkAccess()
      */
-    public final void setName(String name) {
+    public final synchronized void setName(String name) {
         checkAccess();
         this.name = name.toCharArray();
         if (threadStatus != 0) {
             setNativeName(name);
         }