c3p0 Connection Checkin

I'm trying to implement a solution with c3p0 for the first time. I understand how to initialize the connection pool and "checkout" a Connection from the pool as follows:

ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setDriverClass(driverClass);
cpds.setJdbcUrl(url);
cpds.setUser(username);
cpds.setPassword(password);
Connection conn = cpds.getConnection(username, password);

But I am having trouble finding out how to "checkin" an already used Connection to go back into the pool. How would I go about doing th开发者_运维问答is? Is there something that I'm doing wrong here?

Freeing up is totally transparent to the user. See here for further explanation.

Be shure to close() the Connection and hold no further reference (that would avoid proper GC).

I believe the connection is returned to the pool when you close it.