Question

suppose we have these classes and read the comments

class Work {
void doWork(){  }
void commit(){}       
}
class MyRunable implements Runnable {
run(){
   Work  work=new Work();
   work.doWork();
//i can't write work.commit() here, because sometimes i want Thread runs both methods       
 //and sometimes runs only doWork()
 }
}
class Tasks{
main(){
MyRunable myRunable=new MyRunable();
Thread t=new Thread(myRunable);
t.start();
//suppose now i need to call commit() method by the same thread (t)
//how can i do that 
}
}

also i don’t want to use constructor to determine if i want to call both method or not

Answer 1

You could try using a thread pool with a single thread and keep enqueuing methods as needed:

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

        ExecutorService exec = Executors.newSingleThreadExecutor();
        final Work work = new Work();
        exec.submit(new Runnable() {
                public void run() {
                    work.doWork();
                }
            });
        // later
        exec.submit(new Runnable() {
                public void run() {
                    work.commit();
                }
            });

    }
}

This way, both methods will be executed in a sequence by the same thread, but separately.