How to run two threads at the same time in java

Question

I am new to java and I am trying to learn about threads.

I am expecting an output of alternate hello this is thread one and hello this is thread two. but the output I get is as follows:

hello this is thread one
hello this is thread one
hello this is thread one
hello this is thread one
hello this is thread one
hello this is thread two
hello this is thread two
hello this is thread two
hello this is thread two
hello this is thread two

Below is my code. Can anyone please help me out to why I am getting this output as opposed to expected. And what is it that I can do to run the two threads in parallel.

public class ThreadDemo {
    public static void main(String args[]) {

        // This is the first block of code
        Thread thread = new Thread() {
            public void run() {
                for (int i = 0; i < 10; i += 2) {
                    System.out.println("hello this is thread one");
                }
            }
        };

        // This is the second block of code
        Thread threadTwo = new Thread() {
            public void run() {
                for (int i = 0; i < 10; i += 2) {
                    System.out.println("hello this is thread two");
                }
            }
        };

        // These two statements are in the main method and begin the two
        // threads.
        // This is the third block of code
        thread.start();

        // This is the fourth block of code
        threadTwo.start();
    }
}

Answer 1

Just because threads may interlace does not mean that they will. Your threads simply run too fast. Try adding Thread.sleep() to make them run longer.