You should close the result set if you are going to reuse a statement. While not closing it won't kill your application, if the life of the statement is significantly long, you could end up with a lot of unclosed result sets. Keep in mind, garbage collection will not close an object. As Jeanne pointed out, though, you should always close both when you're done with them since you can't predict what a driver is going to do and because its a good practice. Not closing JDBC objects properly can lead to a lot of bugs as an application scales to more and more users.