Yes it does, Connection.close API says "Releases this Connection object's database and JDBC resources immediately instead of waiting for them to be automatically released". The problem is that applications typically use database connection pools and these may simply return Connection to pool on Connection.close.
In any case, it's a good practice to always close ResultSet and Statement explicitly and not to rely on Connection.close.
Besides, it's not the best idea to work with JDBC directly. You can use Spring JDBC instead and forget about releasing resources problem.
