Enums: methods exclusive to each one of the instances

From another question I have learnt that it is possible in Java to define specific methods for each one of the instances of an Enum:

public class AClass {

    private enum MyEnum{
        A { public String method1(){ return null; } },
        B { public Object method2(String s){ return null; } },
        C { public void method3(){ return null; } } ;
    }

    ...
}

I was surprised that this is even possible, do this "exclusive methods" specific to each instance have a name to look for documentation?

Also, how is it supposed to be used? Because the next is not compiling:

    private void myMethod () {
        MyEnum.A.method1();
    }

How am I supposed to use these "exclusive" methods?