Убедись, что для одинаковых объектов возвращает 0.

package com.javarush.task.task17.task1714; /* Comparable */ public class Beach implements Comparable<Beach> { private String name; //название private float distance; //расстояние private int quality; //качество public Beach(String name, float distance, int quality) { this.name = name; this.distance = distance; this.quality = quality; } public synchronized String getName() { return name; } public synchronized void setName(String name) { this.name = name; } public synchronized float getDistance() { return distance; } public synchronized void setDistance(float distance) { this.distance = distance; } public synchronized int getQuality() { return quality; } public synchronized void setQuality(int quality) { this.quality = quality; } public synchronized int compareTo(Beach b2) { int points1 = 0; int points2 = 0; if (this.getDistance() >= b2.getDistance()) points1--; else points2--; if (this.getQuality() >= b2.getQuality()) points1++; else points2++; if (this.name.length() >= b2.name.length()) points1++; else points2++; if (points1 == points2) return 0; else if (points1 > points2) return points1 + 10; else return points2 + 10; } public static void main(String[] args) { } }