小编yi *_*ang的帖子

我有一个关于Java 8的问题Runnable.

 public static void main(String[] args) {
    Runnable r1 = Test::t1;
    Runnable r2 = Test::t2;
    Runnable r3 = Test::t3;
}

public static void t1() {

}

public static String t2() {
    return "abc";
}

public static String t3(String t) {
    return t;
}

正如代码所示,我理解r1是对的,r3也是错的,但我不明白为什么r2也是对的.任何人都可以帮我理解吗？

    byte[] a = {1,2,3};
    System.out.println(Stream.of(a).count());

    Byte[] b = {1,2,3};
    System.out.println(Stream.of(b).count());

结果是1和3,为什么？