[java] What does the hexadecimal conversion Integer.toHexString() in Java do? When will it be used? Why use it? Why is byte &0xff? Why AND with 0xff?

Reference address: http://www.cnblogs.com/think-in-java/p/5527389.html

Reference address: https://blog.csdn.net/scyatcs/article/details/16887807

Reference address: https://blog.csdn.net/wangyang1354/article/details/52290461