Question

Can anyone tell me if I’m right or not? I have two thread which will run in parallel.

class MyThread extends Thread {

    MyThread() {
    }

    method1() {
    }

    method2() {
    }

    method3() {
    }

    approach(1):

        run() {
            method1();
            method2();
            method3();
        }

    approach(2):

        run() {
            //the code of method1 is here (no method calling)
            //the code of method2 is here (no method calling)
            //the code of method3 is here (no method calling)
        }

}

class Test{
    public static void main(){
        Thread t1 = new Thread();
        t1.start();
        Thread t2 = new Thread();
        t2.start();
    }
}

method1, method2 and method3 don’t access global shared data but their codes perform some write in local variable within the method section, thus I guess I can not allow overlap execution within the method section.

Thereby:
in approach(1): I need to make the methods (method1, method2 and method3) synchronized, right?

in approach(2): No need to synchronize the code sections, right?

If I’m right in both approach, using the approach(2) will give better performance, right?

Answer 1

You are saying your methods don’t access global shared data and write only local variables so there is no need to synchronize them Because both the threads will be having their own copies of local variables. They will not overlap or something.

This kind of problem is faced in case of static/class variables. If multiple threads try to change the value of static variables at same time then there comes the problem so there we need to synchronize.