Multithread imbalance Java

Question

This is the code for my thread test.

class TestThread extends Thread {   
    @Override
    public void run() {
        while (true) {
            System.out.println("Run thread "+this.getId());
            try {
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

In the main function, I set up 100 threads:

for (int i = 0; i < 100; i++) {
    TestThread tt = new TestThread();
    tt.run();
}

And this is the result I got

Run thread 8
Run thread 8
Run thread 8
Run thread 8
...

Why only thread 8 printed out? It seems that this is the only thread that is running. How can I make other threads work?

score 4 · Accepted Answer · answered Feb 11 '16 at 17:08

Thread.run will call the threads run-method directly. It will be executed synchronously, not parallel.

To run a thread asynchronously, use Thread.start().

By the way: Extending Thread and starting the thread-objects directly is not recommended. It is usually far better to implement your tasks as a Runnable and then use a ThreadPoolExecutor to implement multithreading.

score 3 · Answer 2 · answered Feb 11 '16 at 17:08

3

to start a thread. use start() method instead of run().

what you're doing now is basically running that function.

answered Feb 11 '16 at 17:08

kucing_terbang

4,991
2
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28

score 0 · Answer 3 · answered Feb 11 '16 at 17:09

0

You should be calling thread. start instead of thread.run.

answered Feb 11 '16 at 17:09

Madhusudana Reddy Sunnapu

8,064
2
18
29

Multithread imbalance Java

3 Answers3