The difference between synchronize and volatile

synchronize and volatile The difference between

1. volatile Can only be used to decorate variables ,synchronize Can be used to modify methods 、 Code block . With jdk Technological development ,synchronize The implementation efficiency will be greatly improved , therefore synchronize It is still common in the project process ;

2. Multithreaded access volatile There will be no blockage ; and synchronize There will be a blockage ;

3. volatile It can ensure the synchronization of variables between private memory and main memory , But the atomicity of variables cannot be guaranteed ;synchronize Variable atomicity can be guaranteed ;

4. volatile Is the visibility of variables between threads ;synchronize Is the synchronization of accessing resources between multiple threads ;　
   about volatile Decorated variable , It can solve the visibility problem of variable reading , There is no guarantee of atomicity . For multiple threads accessing the same instance variable, lock synchronization is still required .