Why does adding a public field to an anonymous class in Java not work?

Question

I have an example class defined like below:

public class FooBar {

  void method1(Foo foo){ // Should be overwritten
    ...
  }

}

Later,

Answer 1

A local class would do

{
    class MyFooBar extends FooBar{
        String name = null;
        ...
    };

    MyFooBar fooBar = new MyFooBar();

    fooBar.name = "Test";
}