Person.java

package chapter11.eight;

public class Person {

	public final String first;
	public final String last;
	public final String address;
	public Person(String first,String last,String address) {
		this.first=first;
		this.last=last;
		this.address=address;
	}
	@Override
	public String toString() {
		// TODO Auto-generated method stub
		return "Person:"+first+"  "+last+"   "+address;
	}
	public static class NullPerson extends Person implements Null{

		public NullPerson() {
			super("none", "none", "none");
			// TODO Auto-generated constructor stub
		}
		@Override
		public String toString() {
			// TODO Auto-generated method stub
			return "NullPerson";
		}
		public static final Person NULL=new NullPerson();
	}
}