What are the differences between synchronized and volatile in Java?

Can you explain the differences between synchronized and volatile in Java?

Sure! In Java, 'synchronized' is a keyword used to control access to a block of code or an object by multiple threads, ensuring that only one thread can execute that block at a time. 'Volatile', on the other hand, is a keyword that indicates that a variable's value will be modified by different threads, ensuring that changes made by one thread are visible to others immediately.

When should I use synchronized instead of volatile?

You should use 'synchronized' when you need to protect a block of code that accesses shared resources to prevent thread interference. Use 'volatile' when you want to ensure visibility of changes to variables across threads without needing to lock the entire block of code.

Can you give an example of when to use each?

Certainly! Use 'synchronized' when updating a shared counter to ensure that increments are atomic. Use 'volatile' for a flag variable that indicates whether a thread should continue running, as you want all threads to see the latest value without locking.

Are there performance implications for using synchronized?

Yes, using 'synchronized' can lead to performance overhead due to thread contention and context switching. It's generally slower than using 'volatile' because it involves acquiring and releasing locks.