Freeing Resources

Every JDBC object consumes some number of resources. A ResultSet object, for example, may contain a copy of every row returned by a query; a Statement object may contain the text of the last command executed, and so forth. It’s usually a good idea to free up those resources when the application no longer needs them. The sample application releases the resources consumed by the Result, Statement, and Connection objects by calling each object’s close() method:

rs.close();
stmt.close();
con.close();

If you attempt to use a JDBC object after closing it, that object will throw an error.