Java, Comparator, 抛出异常: 比较方法未正确实现Comparable接口的compareTo方法

    import com.google.common.collect.Lists;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;
    
    
    class TheShop {
    int brand;
    int distince;
    int modelScore;
    int defaultLevel = 0;
    
    }
    
    public class ComparatorTest {
    private static Comparator<TheShop> FIRST_COMPARATOR = Comparator.comparing(x -> x.defaultLevel);
    
    private static Comparator<TheShop> THE_COMPARATOR = FIRST_COMPARATOR
            .thenComparing((shop1, shop2) -> {
                if (shop1.brand == shop2.brand)