A guide to myself to understand Java Synchronization

Java Syncronization

Without Modifiers:
  Instance methods are async, this means that you can call a method in the same object from different threads at the same time and they will be executed as well *at the same time*, without locking
Synchronized Method:
  Synchronized Methods of the *SAME INSTANCE* can't be in execution at the same time, even if they are different methods.
Synchronized Blocks:
  2 or more synchronized blocks with the same reference (the argument) can't be in execution at the same time.
  Doing a synchronized block with the instance (this) as reference has the same behaviour as a Synchronized Method but with no need of making the entire method synchronized.
  In order to add "global synchronization" on a block, you can set the class of the instance or any other static object as reference.