Thread.sleep in mbean give 100% cpu

[chitech]

I have a mbean to setup the database. But if the database is not available then the mbean will sleep in 5 min and then try again. When the database is up running then the mbean will continue.

When I am using Thread.sleep(300000) in the current thread or do it in a separate thread the cpu will always be 100% when the thread is sleeping. The top linux command show 100% cpu and I can also see new threads is spawn about every 5 seconds (show threads on). I know I have not created these threads

Could it be that jboss find out something is idle and creating new threads?

I am using jboss 4.2.3

[sfisque]

i guess the first question is, why are you spawning a thread inside of an EE container?  you really should be using a Timer.

[chitech]

As I write in the first place. I am not creating any new threads. I just sleeping on the current thread that is executing the mbean. I have also tried to create only one new thread but with same result.

Maybe I can use the Timer class.

my flow for the mbean:

1. check db is running.

2. if not wait 5 min. Then repeat point 1

3. if db running. make a select

4. if select = false -> shutdown

5. if select = true -> continue with the rest

How can I use the Timer to do some task and make the main thread waiting? Must not do anything when the db is down

Something like this:

boolean dbRunning = false;

Timer timer = new Timer();

timer.schedule(new MyTask(), 300000);

while(!dbRunning); // Wait until the db is up running

timer.cancel();

...

...

class MyTask extends TimerTask {

   public void Run() {

    if (db == running) {

       dbRunning = true;

    }

  }

}

[sfisque]

yeah, the entire Thread api is a no-no in a EE contained environment.

that being said, what is it you are trying to really achieve.  i think there might be a subtle misunderstanding of the EE architecture as a whole.

you might be able to achieve the goal in a way that does not violate EE platform semantics.

[chitech]

Problem is now solved. No problem with using Thread with ExecuteService in MBean. The problem was another jboss thread which has causing the high cpu load.