Hi,

Is there any keyword or design pattern for doing this?

public abstract class Root
{
    public abstract void foo();
}

public abstract class SubClass extends Root
{
    public void foo()
    {
        // Do something
    }
}

public class SubberClass extends SubClass
{
    // Here is it not necessary to override foo()
    // So is there a way to make this necessary? 
    // A way to obligate the developer make again the override 
}

Thanks