Q65.What is the Thread Local?
Ans.  It's a way for each thread in multi-threaded code to keep its own copy of an instance variable. Generally, instance variable are shared between all threads that use an object; ThreadLocal  is a way for each thread to keep its own copy of such a variable. The purpose might be that each thread keeps different data in that variable, or that the developer wants to avoid the overhead of synchronizing access to it.
Q66. In your previous project where you used multithreading concept?