What are Shadow Variables in Java?

Instead of providing my own description, I may ask you to read about it, for example, here: http://en.wikipedia.org/wiki/Variable_shadowing . Once you understand variable shading, I recommend that you continue reading about overlay / shadow and visibility techniques in general to get a complete understanding of such terms.

In fact, since the question is asked in Java terms, here's a mini example:

    public class Shadow {

        private int myIntVar = 0;

        public void shadowTheVar(){

            // since it has the same name as above object instance field, it shadows above 
            // field inside this method
            int myIntVar = 5;

            // If we simply refer to 'myIntVar' the one of this method is found 
            // (shadowing a seond one with the same name)
            System.out.println(myIntVar);

            // If we want to refer to the shadowed myIntVar from this class we need to 
            // refer to it like this:
            System.out.println(this.myIntVar);
        }

        public static void main(String[] args){
            new Shadow().shadowTheVar();
        }
    }