synchronized关键字解释为同步，那它到底同步了什么？

Java Synchronization and concurrency

The words synchronization and concurrency are overlapping and sometimes synonymous terms. The word synchronization generally means sharing data between multiple processors or threads, while concurrency refers to a measure of– or the art of improving– how effectively an application allows multiple jobs required by that application (e.g. serving web page requests from a web server) to run simultaneously.

 

同步的含义是在多处理器和线程间实现数据共享，也就是所谓的同步了，至于加了synchronized之后有线程间有互斥效果，就不是同步字面含义强调之重点了

 

http://www.javamex.com/tutorials/synchronization_concurrency_1.shtml

 

我目前的理解是这样的。