Why can an Object member variable not be both final and volatile in Java?

Question

If in a class I have a ConcurrentHashMap instance that will be modified and read by multiple threads I might define like this:

public class My Class {

    p         


        

Answer 1

Because it doesn't make any sense. Volatile affects object reference value, not the object's fields/etc.

In your situation (you have concurrent map) you should do the field final.