At the end of your JDBC program, it is required explicitly to close all the connections to the database to end each database session. However, if you forget, Java's garbage collector will close the connection when it cleans up stale objects.
Relying on the garbage collection, especially in database programming, is a very poor programming practice. You should make a habit of always closing the connection with the close() method associated with connection object.
To ensure that a connection is closed, you could provide a 'finally' block in your code. A finally block always executes, regardless of an exception occurs or not.
To close a JDBC connection, you should call close() method as: