On 8/11/2011 4:28 AM, chris hegarty wrote:
In similar tests I've preferred to use j.u.c.Paser/CountDownLatch to coordinate between threads. So, you could completely remove the sleep(1000) from the run method and use a Phaser.arriveAndAwaitAdvance(). This will guarantee both threads will reach a particular point before invoking stop on the group. That way, either thread can invoke stop and set the flag to prevent the other thread from invoking stop too ( if it were to get there! ).
FYI for what this test is testing the requirement is that the first thread issue that group.stop().
David
I agree with Rémi's comments about wait/notify. My comments (above) should work with well with his suggestion. Then no more nasty sleeps! Thanks, -Chris. On 07/11/2011 16:03, Gary Adams wrote:Here's another test with race conditions built into the test that can be easily avoided CR#7084033 - TEST_BUG: test/java/lang/ThreadGroup/Stop.java fails intermittently There are at least two race conditions in the test as currently written. The test uses sleeps as a way to yield time to other threads to complete their tasks, but this may not be sufficient on slower machines. The first race condition is in the starting of the test threads. To ensure both threads are started, the run check for the first thread should also check that the second thread is not null. The second race condition in the main thread presumes that the group stop has been issued within 3000 milliseconds. A simple loop on the delay can be gated by a flag set after the group stop has been issued. diff --git a/test/java/lang/ThreadGroup/Stop.java b/test/java/lang/ThreadGroup/Stop.java --- a/test/java/lang/ThreadGroup/Stop.java +++ b/test/java/lang/ThreadGroup/Stop.java @@ -32,6 +32,7 @@ private static Thread first=null; private static Thread second=null; private static ThreadGroup group = new ThreadGroup(""); + private static boolean groupStopped =false ; Stop() { Thread thread = new Thread(group, this); @@ -47,8 +48,11 @@ while (true) { try { Thread.sleep(1000); // Give other thread a chance to start - if (Thread.currentThread() == first) + if ((Thread.currentThread() == first) + && (second != null)) { + groupStopped = true; group.stop(); + } } catch(InterruptedException e){ } } @@ -57,7 +61,10 @@ public static void main(String[] args) throws Exception { for (int i=0; i<2; i++) new Stop(); + do { Thread.sleep(3000); + } while (!groupStopped) ; + boolean failed = second.isAlive(); first.stop(); second.stop(); if (failed)
