Question

When I put the code below in NetBeans, NetBeans gives me a warning next to it saying “Accessing static method sleep”.

        try {
            Thread.currentThread().sleep(2000);
        }
        catch(InterruptedException ie){
            //continue
        }

Am I doing something wrong? Should I be calling this differently? I’m not doing anything multi-threaded. I just have a simple main method that which I want to sleep for a while.

Answer 1

Thread.currentThread() returns an instance of the Thread class. When invoking a static method you only want to work on the class itself. So invoking a static method on current thread you will get a warning you are calling the method on an instance.

You would just call Thread.sleep(2000); It would be equivalent to Thread.currentThread.sleep(2000);

This is important to know because people have been burned doing something like:

Thread a = new Thread(someRunnable);

a.start();
a.sleep(2000);  //this will sleep the current thread NOT a.

Edit: So how do we sleep a? You sleep a by writing the sleep invocation within the runnable passed in to the constructor, like:

Runnable someRunnable = new Runnable(){
    public void run(){
        Thread.sleep(2000);
    }
};

When ‘a’ is started, Thread.currentThread in someRunnable’s run method is the ‘a’ thread instance.