My Key value pair class

public class KeyValuePair<Key, Value> {

    private Key key;
    private Value value;
    private final boolean isEmpty;

    public KeyValuePair(Key key, Value value){
        this.key = key;
        this.value = value;
        isEmpty = false;
    }

    private KeyValuePair(){
        isEmpty = true;
    }

    public static KeyValuePair getEmpty(){
        return new KeyValuePair();
    }


    public Key getKey(){
        return key;
    }

    public Value getValue(){
        return value;
    }

    public boolean hasValue(){
        return (! isEmpty);
    }
}