Pair java

public class Pair<T1 , T2> {
    T1 x;
    T2 y;
    Pair(T1 _x , T2 _y){
        x = _x;
        y = _y;
    }
    T1 first(){
        return x;
    }
    T2 second(){
        return y;
    }

    public boolean equals(Object other){
        if (other instanceof Pair) {
            Pair otherPair = (Pair) other;
            return
            ((  this.x == otherPair.x ||
                ( this.x != null && otherPair.x != null &&
                  this.x.equals(otherPair.x))) &&
             (  this.y == otherPair.y ||
                ( this.y != null && otherPair.y != null &&
                  this.y.equals(otherPair.y))) );
        }
        return false;
    }

    public int hashCode(){
        int hash = 31;
        int res = 1;
        res = hash * res + x.hashCode();
        res = hash * res + y.hashCode();
        return res;
    }
}