CODEWITHSUNDEEP
javamultithreading
v11
v11

Reputation: 2244

The functionalities of two lines of code

I'm learning about the threads in Java. I want to know whether the following two pieces of code are the same:

 class B extends Thread {
    public void run() {
        doSomething();
    }
    public void doSomething() {}
}
class A extends Thread { 
    public void run() {
        new B().start();
    }
}

The second piece of code is changing the class A:

class A extends Thread {
        public void run() {
            new B().doSomething();
        }
}

When I read the code of my team's project, I find this problem: A thread invoking another thread without loop.

Upvotes: 0

Views: 73

Answers (2)

DNA
DNA

Reputation: 42617

These two cases are not the same, as your question already suggests.

Assuming that in each case we enter the code by calling new A().start(), then the first example starts a thread (A) which starts another thread (B) which calls doSomething().

The second case starts a single thread (A) which calls B.doSomething(). In this case we don't start a thread of type B, because we never call .start() on an instance of B.

Upvotes: 2

shlomi33
shlomi33

Reputation: 1568

In the first snippet you are actually creating a new thread and the invocation of doSomething() is in a separate thread to what A's run() method is running in,

In the second snippet you are execution B's doSomething() in the context (thread) that A is running in.

Upvotes: 0

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