Loader mock server

Reading @ThreadSafe documentation says that it is just to denote that class is thread safe. This annotation doesn't make the class thread safe.  Which means we will need to add synchronisation to all static methods used.

From the java doc

****This annotation does not imply that a sequence made up of calls to methods of this class or accesses to fields of this class are atomic. It is a the responsibility of the caller to insure that such sequences execute atomically.****