Statement#getGeneratedKeys() returns two rows if ON DUPLICATE KEY UPDATE statement updated a row

  @Test

  public void shouldDuplicateKeyUpdateNotReturnExtraRows() throws Throwable {

    try (Connection con = openNewConnection(connUri, new Properties())) {

      try (Statement stmt = con.createStatement()) {

        stmt.execute("truncate table testMultiGeneratedKey");

      }

      try (PreparedStatement pstmt = con.prepareStatement(

          "INSERT INTO testMultiGeneratedKey (id, text) VALUES (?, ?) "

              + "ON DUPLICATE KEY UPDATE text = VALUES(text)",

          Statement.RETURN_GENERATED_KEYS)) {

        // Insert a row.

        pstmt.setInt(1, 1);

        pstmt.setString(2, "initial");

        assertEquals(1, pstmt.executeUpdate());

        try (ResultSet rs = pstmt.getGeneratedKeys()) {

          assertTrue(rs.next());

          assertEquals(1, rs.getInt(1));

          assertFalse(rs.next());

        }

        // Update the row.

        pstmt.setInt(1, 1);

        pstmt.setString(2, "updated");

        assertEquals(2, pstmt.executeUpdate());

        try (ResultSet rs = pstmt.getGeneratedKeys()) {

          assertTrue(rs.next());

          assertEquals(1, rs.getInt(1));

          assertFalse(rs.next());

        }

      }

    }

  }