Oracle query returns every expected record twice

Question

I have a query that at times could return a very large number of records, but I want to process them in blocks within a time budget, so I will process as many as I can within a time budget and then close the ResultSet. I looked at the two obvious ways to control how many rows I get back, using "ROWNUM <= N" and "setFetchSize()".
I think the latter is the more common way of doing this, but I noticed that it's considered a "hint". I think it's likely it would always be used, but because of that small doubt I decided to try using the "ROWNUM <= N" strategy first.
It seemed to be working fine, but I noticed an oddity where it was often returning all the relevant rows twice. I'd gotten the set of records to operate on down to a very small number (8), and I entered the query it uses directly into a SQL browser, and it returned the 8 records I expected. My query was using "ROWNUM <= 20". I stepped into the ResultSet "next()" loop, and I watched it process the 8 records, and then instead of returning "false" from the following call to "rs.next()", it returned true and started at the beginning of the 8 records again. It eventually processed all 8 records twice.
So, I just tried changing it from using "ROWNUM" to using "setFetchSize()". The results were exactly the same. It still processed all 8 records twice.
The query is very simple. It just looks like this, with most of the column names removed, and the table name changed:
SELECT ID, ... FROM TABLE_NAME tn WHERE tn.CREATION_DATE = ?
The somewhat elided code for the loop looks like this:
try {
rs = getRecords(connection);
// Indicates whether at least one row was found.
boolean foundOne = false;
while (rs.next()) {
foundOne = true;
final Record record = makeRecord(rs);
processRecord(record, counters);
++ recordsProcessed;
if (!foundOne) {
break;
if (overTimeBudget(startTime)) {
break;
logInfo("Processed " + recordsProcessed + " record" +
(recordsProcessed == 1 ? "" : "s") + " so far.");
What could be going wrong here?

Answer 1

Never mind. Dumb mistake. It wasn't an Oracle problem. I was doing the query inside a loop because of an earlier design decision.