Lambda表达式

普通：
        String [] names={"mushroom","peach","appl","banana"};
        Comparator comparator=new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return o1.length()-o2.length();                  //[appl, peach, banana, mushroom]
            }
        };
Lambda方式:
　　　　

　　　　　　Comparator<String> comparator=(String name1,String name2)->name1.length()-name2.length(); //[appl, peach, banana, mushroom]

          Comparator<String> comparator=(name1 , name2)->name1.length()-name2.length();  //[appl, peach, banana, mushroom]

 * @see Executor
 * @since 1.5
 * @author Doug Lea
 * @param <V> the result type of method {@code call}
 */
@FunctionalInterface
public interface Callable<V> {
    /**
     * Computes a result, or throws an exception if unable to do so.
     *
     * @return computed result
     * @throws Exception if unable to compute a result
     */
    V call() throws Exception;
}

@FunctionalInterface
public interface Comparator<T> {

    int compare(T o1, T o2);

    boolean equals(Object obj);

    default Comparator<T> reversed() {
        return Collections.reverseOrder(this);
    }

    default Comparator<T> thenComparing(Comparator<? super T> other) {
        ...
    }
    
}