MongoConnector should have a method for closing connections

[laserval]

There is no method for closing the connection that a MongoConnector has to mongoDB.

This means you must always reuse the connector when talking to MongoDB, otherwise there will be open connections left in memory.

[remen]

Make sure that MongoConnector implements the "closeable" interface. That way, one can (in java 7) write:

try(connector = new MongoConnector()) {
    ...
}

which closes the connector automatically when exiting the block (even in case of exception).