An update is not a query.
Don't use "executeQuery", just use executeUpdate
eg
String updateStatement =
"update MY_TABLE" +
"set COL = COL + ? " +
"where BLAH = ?";
try {
con.setAutoCommit(false);
updateTotal = con.prepareStatement(updateStatement);
updateTotal.setInt(1, ...);
updateTotal.setString(2, ...);
updateTotal.executeUpdate();
con.commit();
}