Concurrency handling correct?

Question

Proxy will be called from multiple thread, and Proxy.setWorker() may be called at some time, does anyone know if below implementation will cause problem?

class Worker {
    void methodA() {
        ...
    }
    
    void methodB() {
        ...
    }
};

… and …

class Proxy {
    volatile Worker mWorker;
    final boolean cond= true;
    
    public void setWorker(Worker worker) {
        mWorker = worker;
    }
    void methodA() {
        if(cond)
            mWorker.methodA();
    }
    
    void methodB() {
        if(cond)
            mWorker.methodB();
    }       
}

Answer 1

You get a data race when there are 2 threads doing a read/write or write/write to the same field and these reads/writes are not ordered by the happens-before relation (so there is no happens-before edge between them).

The 'worker' field is volatile, so there is a happens-before edge due to the volatile variable rule; hence, there is no data-race.

I would make the 'cond' field final if possible to prevent confusion. If you would modify the 'cond' field, then your code could have a data-race unless you make it volatile.