CODEWITHSUNDEEP
java
hnimnart
hnimnart

Reputation: 95

Java Thread StackOverflowError

...

Thread showWordThread = new Thread() {
    public void run() {
            try {
                sleep(config.delayTime * 1000);
            } catch (Exception e) {
                System.out.println(e.toString());
            }
            this.run();
        }
    };
    showWordThread.run();
}

...

It had run for about 5 minutes before error occured:

Exception in thread "Thread-2" java.lang.StackOverflowError.

Why?

I had tried this:

Thread showWordThread = new Thread(new Runnable() {
        public void run() {
            while (true) {
                try {
                    Thread.sleep(config.delayTime * 1000);
                } catch (Exception e) {
                    System.out.println(e.toString());
                }
            }
        }
    });
    showWordThread.start();

But error still occured.

Upvotes: 1

Views: 4310

Answers (6)

Jon Skeet
Jon Skeet

Reputation: 1499860

Others have explained that you should use a while loop instead. You're also trying to call the run method inside your anonymous class declaration. Additionally, you should call start, rather than run - when the new thread has started, it will call run automatically. I'd actually suggest implementing Runnable rather than extending Thread, too. So you want:

Thread showWordThread = new Thread(new Runnable() {
    @Override public void run() {
        while (someCondition) {
            try {
                Thread.sleep(config.delayTime * 1000);
                // Presumably do something useful here...
            } catch (Exception e) {
                System.out.println(e.toString());
            }
        }
    }
});
showWordThread.start();

Alternatively, consider using a Timer or ScheduledExecutorService.

Upvotes: 4

Pau Kiat Wee
Pau Kiat Wee

Reputation: 9505

Your code have infinity recursive, you should change the code to:

    Thread showWordThread = new Thread() {
        public void run() {
            while (true) {
                try {
                    Thread.sleep(config.delayTime * 1000);
                } catch (Exception e) {
                    System.out.println(e.toString());
                }
            }
        }
    };
    showWordThread.start();

Upvotes: 1

Sam
Sam

Reputation: 6890

You are calling run method as recursively. Java holds call information(such as parameters) in stack memory so when you are calling a method recursively and there isn't any end point, stack memory will consumed and StackOverflow exception throws.

Maybe you want increasing Heap Size of JVM but this solution don't solve your problem and StackOverflow will occurred .

I guess you want run a thread continually. I recommend following code:

Thread showWordThread = new Thread() 
{
    public void run() 
    {
            try 
            {
                sleep(config.delayTime * 1000);
            } 
            catch (Exception e) 
            {
                System.out.println(e.toString());
            }
            // this.run(); this snnipet code  make error
        }
    };
    showWordThread.run();
}

Upvotes: 2

mprivat
mprivat

Reputation: 21902

Don't call run() from within the run() method. That'll definitely produce a stack overflow because you keep reentering the same method with no exit condition. Instead use a while loop.

Thread showWordThread = new Thread() {
    public void run() {
        while(condition) {
            try {
                sleep(config.delayTime * 1000);
            } catch (Exception e) {
                System.out.println(e.toString());
            }
        }
    };
    showWordThread.start();
}

Upvotes: 1

mindas
mindas

Reputation: 26713

Maybe because you call run method (this.run()) from itself?

Upvotes: 0

SLaks
SLaks

Reputation: 887275

Your function calls itself each time you run it.
That results in a stack overflow.

Upvotes: 0

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