Question

Consider the following code snippet:

public void getUsers() {
    CachedRowSet rowSet = new CachedRowSetImpl();
    .........     /* Initialize the rowset */
    String query = "SELECT user_id FROM users";
    rowSet.setCommand(query);
    rowSet.execute();
    .........    /* Do some job */

}

Here the CachedRowSet object is used locally in a method. Do I need to manually close it here or the contents it holds will be grabage collected automatically when the method finishes?

Answer 1

from: http://docs.oracle.com/javase/1.5.0/docs/api/javax/sql/rowset/CachedRowSet.html

A CachedRowSet object is a disconnected rowset, which means that it
makes use of a connection to its data source only briefly. It connects
to its data source while it is reading data to populate itself with
rows and again while it is propagating changes back to its underlying
data source. The rest of the time, a CachedRowSet object is
disconnected, including while its data is being modified. Being
disconnected makes a RowSet object much leaner and therefore much
easier to pass to another component. For example, a disconnected
RowSet object can be serialized and passed over the wire to a thin
client such as a personal digital assistant (PDA).

that means there is no connection issue to close
so u can leave it

but i think its good practice to always close what you open and not leave it to the GC which you usually don’t touch or tell when to run.

given a large enough server with many requests, if it causes open file descriptors it can eventually be an issue.
making sure resources are closed is always best