Notes on synchronized modified classes

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Notes for synchronized modified classes

The following author describes the precautions for the use of synchronized modified keywords, as follows:

1. When a thread accesses a "synchronized method" or "synchronized code block" of "an object"Access by other threads to this "synchronized method" or "synchronized code block" of "this object" will be blocked2. When a thread accesses a "synchronized method" or "synchronized code block" of "an object"Other threads can still access unsynchronized code blocks of "this object"3. When a thread accesses a "synchronized method" or "synchronized code block" of "an object"Access by other threads to other "synchronized methods" or "synchronized code blocks" of "this object" will be blocked4. The synchronized keyword is added to the method or object,then the lock it acquires is the object5.The object of synchronized action is a static method or a classThen the lock it acquires is for the class, and all objects of this class have the same lock