关于java:当一个值被赋值为null引起的javalangNullPointerException

上代码

String ss = null;

// false
System.out.println(ss == "");
// 报错 java.lang.NullPointerException
// System.out.println(ss.equals(""));

// false
System.out.println(Objects.equals(ss,""));


Long id = null;

System.out.println(id);

// 报错
System.out.println(id == 0);
// false
System.out.println(Objects.equals(id,0));
// true
System.out.println(Objects.equals(id,null));

总结

当前是不是用到比拟的时候,都须要用objects.equals??