How to use java 8 comparator

public class Apple implements Comparable<Apple> {
    private int id;
    private Color color;
    private int weight;
    //constructor
    public Apple(int id, Color color, int weight) {
        this.id = id;
        this.color = color;
        this.weight = weight;
    }  
   // Here we implement the compareTo() method of the Comparable interface.    
    @Override
    public int compareTo(Apple apple) {
        return this.getColor().compareTo(apple.getColor());
    }
    // getters / setters and toString()
    //
    //
    enum Color {
        RED, GREEN
    }
}