After patching 5104215 fix(that is a fix in jdk5.0u6), the attached 
test program can not watch that the thread becomes BLOCKED state.

Below is the snippet related to Thread.State from JDK 5.0 API's doc.
http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.State.html
-----
BLOCKED
Thread state for a thread blocked waiting for a monitor lock. A thread
in the blocked state is waiting for a monitor lock to enter a
synchronized block/method or reenter a synchronized block/method after
calling Object.wait.

WAITING
Thread state for a waiting thread. A thread is in the waiting state
due to calling one of the following methods:
Object.wait with no timeout 
Thread.join with no timeout 
LockSupport.park 
A thread in the waiting state is waiting for another thread to perform
a particular action. For example, a thread that has called
Object.wait() on an object is waiting for another thread to call
Object.notify() or Object.notifyAll() on that object. A thread that
has called Thread.join() is waiting for a specified thread to
terminate.  
-----

Test Program:
-----
public class MustBeBlocked extends Thread {
  static Object _lock = new Object();

  public static void main(String[] args) throws Exception {
    Thread t = new MustBeBlocked();
    t.start();
    
    do {
      Thread.sleep(100);
    }while(t.getState()!=Thread.State.WAITING);

    synchronized(_lock) {
      _lock.notify();
      while( t.getState()==Thread.State.WAITING) {  // Must be BLOCKED
        System.out.println("waiting .."); 
        Thread.sleep(1);
      }
      System.out.println( t.getState()); 
    }
    System.exit(0);
  }

  public void run() {
    try { run0();}
    catch(Exception e){e.printStackTrace();}
  }
  
  public void run0() throws Exception{
    synchronized(_lock) {
      _lock.wait();
    } 
  }
}
-----
The TP's purpose is based on API's BLOCKED part "or reenter a
synchronized block/method after calling Object.wait.".
main() watches if the thread will become BLOCKED state after it is
notified from wait(). When the state becomes BLOCKED, the program 
will exit.

Expected result:
(1) JDK5.0u5
# java MustBeBlocked
waiting ..
BLOCKED

Current result:
(2) JDK5.0u12(b04)
# java MustBeBlocked
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
...

(3) JDK6u2(b02)
# java MustBeBlocked
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
waiting ..
...