Java中双冒号::的实现示例

1. Lambda表达式表达式：
person -> person.getName();
可以替换成：
Person::getName

2. Lambda表达式表达式：
() -> new HashMap<>();
可以替换成：
HashMap::new

public class Test07 {
    public static void a(){
        System.out.printf("a1");
    }
    public static void a(String s){
        System.out.printf(s);
    }
    public static void main(String[] args) {
        Runnable runnable=Test07::a;
        runnable.run();
    }
}

public class Test07 {
    public static void a() {
        System.out.printf("a1");
    }

    public static void a(String s) {
        System.out.printf(s);
    }

    public static void main(String[] args) {
        Consumer<String> consumer=Test07::a;
        consumer.accept("调用有参的方法a");
    }
}

    public static void a(String s1,String s2) {
        System.out.printf(s1+s2);
    }

    public static void main(String[] args) {
        BiConsumer<String,String> biConsumer=Test07::a;
        biConsumer.accept("测试","数据");
    }

public class Test07 {
    public static String b(){
        return "b";
    }
    public static void main(String[] args) throws Exception {
        Callable<String> runnable=Test07::b;
        String s=runnable.call();
        System.out.printf(s);
    }
}