Is SpotBugs reporting a false positive on not closing a resource here?

Question

I have code like this:

public static MyObject forId(long myObjectId, Connection cxn) throws SQLException {
    try (PreparedStatement stmt = cxn.prepareStatement(selectMyObjectById))) {
        stmt.setLong(1, myObjectId);
        try (ResultSet res = stmt.executeQuery()) {
            res.next();
            return MyObject.fromResultSet(res);
        }
    }
}

which SpotBugs identifies as OBL_UNSATISFIED_OBLIGATION for the JDBC Statement object. Is this a false positive? My impression is that try-with-resources will ensure these resources get closed properly in all cases.

Answer 1

Your ResultSet and PreparedStatement are protected as you rightly state.

If your Connection is also appropriately handled in the relevant scope then yes, it is a false positive.

Answer 2

The scenario in question is definitely a false positive.

There are multiple issues with Spotbugs (as of 3.1.5):

1. AutoCloseable objects used within try-with-resources are reported by SpotBugs (false positives):

   • https://github.com/spotbugs/spotbugs/issues/493

2. There's also an issue related specifically to ResultSet and Statement ("closing a statement implicitly closes the result set obtained from it"):

   • https://github.com/spotbugs/spotbugs/issues/79
   • https://github.com/findbugsproject/findbugs/issues/99