Lambdas表达式示例

代码如下：

import java.util.*;public class Lambdas {    public static void main(String ...args){        // Simple example        Runnable r = () -> System.out.println("Hello!");        r.run();        // Filtering with lambdas        List<Apple> inventory = Arrays.asList(new Apple(80,"green"), new Apple(155, "green"), new Apple(120, "red"));        // [Apple{color='green', weight=80}, Apple{color='green', weight=155}]          List<Apple> greenApples = filter(inventory, (Apple a) -> "green".equals(a.getColor()));        System.out.println(greenApples);        Comparator<Apple> c = (Apple a1, Apple a2) -> a1.getWeight().compareTo(a2.getWeight());        // [Apple{color='green', weight=80}, Apple{color='red', weight=120}, Apple{color='green', weight=155}]        inventory.sort(c);        System.out.println(inventory);    }    public static List<Apple> filter(List<Apple> inventory, ApplePredicate p){        List<Apple> result = new ArrayList<>();        for(Apple apple : inventory){            if(p.test(apple)){                result.add(apple);            }        }        return result;    }       public static class Apple {        private int weight = 0;        private String color = "";        public Apple(int weight, String color){            this.weight = weight;            this.color = color;        }        public Integer getWeight() {            return weight;        }        public void setWeight(Integer weight) {            this.weight = weight;        }        public String getColor() {            return color;        }        public void setColor(String color) {            this.color = color;        }        public String toString() {            return "Apple{" +                    "color='" + color + '\'' +                    ", weight=" + weight +                    '}';        }    }    interface ApplePredicate{        public boolean test(Apple a);    }}