Synchronized detailed parsing

1. We all know that the code we write will be compiled to jvm management , How to manage it ？ There must be something to add

This thing is the object header , Mark something , For example, today's lock , also gc Related things Here's the picture

2.jvm How to write

        Omit ... I don't want to find ...（ I guess I can't remember later ）

3.synchronized The lock has an upgrade process , From no lock --》 Biased locking --》 Lightweight lock ---》 Heavyweight lock , According to the above process Summarize the process

3.1） Bias lock process

 

3.2） Lightweight lock

 

 

 

 3.3） Heavyweight lock

Lock process

 

  Exit process