Advanced Multi threading Concepts

Thread Group

Based on functionality we can group threads into a single unit which is nothing but a Thread Group. That is Thread Group contains a group of threads.In addition to threads, Thread Group can also contains sub Thread Groups.

The main advantage of maintaining threads in a form of Thread Group is we can perform common operations very easily. Every thread in java belongs to some group. Main thread belongs to Main Group. Every Thread Group in java is a child thread of System Group either directly or indirectly hence System Group acts as root for all Thread Groups in Java. System Group contains several system level threads like Finalizer, Reference Handler, Single Dispatcher, Attach Listener etc.