Execute the following code with Concurrency preliminary test release 1
and see the result. contains() method doesn't return correct boolean value.
It return false even if the element is present.

/* start of sample test code */
//If the array ArrayBlockingQueue size is 3, then contains() method of the queue
//doesn't return correct boolean value. But if the array size is 4, it works correctly.
ArrayBlockingQueue < String > queue = new ArrayBlockingQueue < String> (3);
// Code doesn't works if used above constructor.

//ArrayBlockingQueue < String > queue = new ArrayBlockingQueue < String> (4);
// Code works if used above constructor.
       
queue.add("str1");
queue.add("str2");
queue.add("str3");
               
ArrayList list = new ArrayList();
list.add("str1");
list.add("str2");
System.out.println("status = " + queue.contains("str1"));
System.out.println(queue.toString());
/* end of sample test code */

This is only a backlog bug and added to bugtraq just for tracking purpose.
It has been fixed.