Question

Should I explicitly set thread reference to null after thread completes it’s work or it’s not necessary? If I want to set it as null then where in the code should I do this?

Should I check if thread is alive or not using thread.isalive flag and then set it to null if it’s not alive?

Answer 1

Should i explicitly set thread reference to null after thread
completes it’s work or it’s not necessary?

Personally, I would not bother. There are a few cases where explicitly setting object references to null really matters anyway. Regardless of type those cases are:

• If the variable is a static member and the object it references consumes a lot of memory.
• If the variable is an instance member contained within a longer living object which references an object that consumes a lot of memory.
• If the variable is a local to a long running method which references an object that consumes a lot of memory.¹

Those are the ones I could think of. Perhaps there are more, but probably not many. The common denominator here is that the variable references an object that consumes a lot of memory. The managed Thread object itself is not going to consume a lot of memory so I cannot imagine that setting a variable of type Thread to null is going to accomplish a whole lot for you regardless of how it is used. Most of the resources are allocated when the thread starts and then get deallocated when the thread ends.

Should i check if thread is alive or not using thread.isalive flag and
then set it to null if it’s not alive.

I prefer to use Thread.Join to test and wait for the completion of a thread. In fact, I have never used Thread.IsAlive for anything useful…ever.

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¹The GC is actually smart enough to dispose local object references before a method ends if it can detect that the reference is no longer used.