How can I use the volatile keyword in Java correctly?

Question

Say I have two threads and an object. One thread assigns the object:

public void assign(MyObject o) {
    myObject = o;
}

Another thread uses t

Answer 1

You can use volatile in this case. You will require volatile, synchronization around the access to the variable or some similar mechanism (like AtomicReference) to guarantee that changes made on the assignment thread are actually visible to the reading thread.