gistfile1.java

class Test {
    
    public static abstract class Base {
	
	public Base (int x) { initialize (x); }

	protected String value;

	private void initialize (int x) {
	    
	    value = Integer.toString (x) + getFoo ();
	}

	public abstract String getFoo ();

	@Override
	public String toString () { return value; }
    }

    public static class Derived extends Base {
	public Derived (int x) {
	    super (x);
	    foo = "foo";
	}

	private String foo;

	@Override
	public String getFoo () { return foo; }
    }

    
    public static void main (String [] args)
    {
	Derived d = new Derived (3);
	System.out.println (d);
    }
}