Comparator<Transaction> byYear = new Comparator<Transaction>() {

            @Override            public int compare(Transaction o1, Transaction o2) {                return o1.getValue().compareTo(o2.getValue());

            }

        };

Comparator<Transaction> byYear = (o1, o2) -> o1.getValue().compareTo(o2.getValue());

(List<String> list) -> list.isEmpty();

() -> new Transaction();

(Transaction t) -> {

            System.out.println("Year = " + t.getYear());

}

(String s) -> s.length();

(int a, int b) -> a * b;

Runnable r2 = new Runnable() {//使用匿名类            @Override            public void run() {

                System.out.println("hello world 2");

            }

        };

        process(r1);//打印hello world 1

        process(r2);//打印hello world 2

        process(()-> System.out.println("hello world 3"));//利用直接传递Lambda表达式作为实现实例 打印hello world 3

/**

 * The <code>Runnable</code> interface should be implemented by any

 * class whose instances are intended to be executed by a thread. The

 * class must define a method of no arguments called <code>run</code>.

 * <p>

 * This interface is designed to provide a common protocol for objects that

 * wish to execute code while they are active. For example,

 * <code>Runnable</code> is implemented by class <code>Thread</code>.

 * Being active simply means that a thread has been started and has not

 * yet been stopped.

 * <p>

 * In addition, <code>Runnable</code> provides the means for a class to be

 * active while not subclassing <code>Thread</code>. A class that implements

 * <code>Runnable</code> can run without subclassing <code>Thread</code>

 * by instantiating a <code>Thread</code> instance and passing itself in

 * as the target.  In most cases, the <code>Runnable</code> interface should

 * be used if you are only planning to override the <code>run()</code>

 * method and no other <code>Thread</code> methods.

 * This is important because classes should not be subclassed

 * unless the programmer intends on modifying or enhancing the fundamental

 * behavior of the class.

 *

 * @author  Arthur van Hoff

 * @see     java.lang.Thread

 * @see     java.util.concurrent.Callable

 * @since   JDK1.0 */@FunctionalInterfacepublic interface Runnable {    /**

     * When an object implementing interface <code>Runnable</code> is used

     * to create a thread, starting the thread causes the object's

     * <code>run</code> method to be called in that separately executing

     * thread.

     * <p>

     * The general contract of the method <code>run</code> is that it may

     * take any action whatsoever.

     *

     * @see     java.lang.Thread#run()     */

    public abstract void run();

}

List<Apple> inventory = new ArrayList<>();

inventory.sort(Comparator.comparing(Apple::getWeight)//按重量排序

 .reversed()//递减 倒序

 .thenComparing(Apple::getCountry));//如果重量一样 按国家排序