Do I need to explicitly close connection?

Question

I\'m holding one instance of MongoClient and DB in my application, and every time that I want to execute some operation I call getCollection(

Answer 1

No, you do not need to close connections to DB - your only connection is via MongoClient and as the documentation states - it handles connection pooling for you.

The only resource that you would want to clean up would be a cursor which you should close() when you're done with it.