Java - Multithreading !

Question

What does phrase "synchronization with main memory" mean?

Answer 1

http://www.javamex.com/tutorials/synchronization_concurrency_synchronized2.shtml

Answer 2

When you have multiple threads each thread may keep a local copy of a variable's value. However the "official copy" of the value is kept in main memory. So what that phrase means is that any local copy of a variable's value will be made consistent with main memory (either reading to check for updates, or writing to publish updates made to the local copy).