* @param columnKey column key that the value should be associated with
   * @param value value to be associated with the specified keys
   * @return the value previously associated with the keys, or {@code null} if no mapping existed
   *     for the keys
   */
  @CanIgnoreReturnValue
  @Nullable V put(
      @ParametricNullness R rowKey, @ParametricNullness C columnKey, @ParametricNullness V value);

  /**

        try {
            String result = SystemUtil.getSearchEngineHttpAddress();
            assertNull(result);
        } finally {
            // Restore original value if it existed
            if (originalValue != null) {
                System.setProperty(Constants.FESS_SEARCH_ENGINE_HTTP_ADDRESS, originalValue);
            }
        }
    }

   * in any particular order. The returned {@code Iterator} is a "weakly consistent" iterator that
   * will never throw {@link ConcurrentModificationException}, and guarantees to traverse elements
   * as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect
   * any modifications subsequent to construction.
   *
   * @return an iterator over the elements in this queue
   */

   * Iterator} is a "weakly consistent" iterator that will never throw {@link
   * ConcurrentModificationException}, and guarantees to traverse elements as they existed upon
   * construction of the iterator, and may (but is not guaranteed to) reflect any modifications
   * subsequent to construction.
   *
   * @return an iterator over the elements in this queue in proper sequence
   */

   * are valid.
   *
   * @param rowKey row key of mapping to be erased
   * @param columnKey column key of mapping to be erased
   * @return the value previously associated with the keys, or {@code null} if no mapping existed
   *     for the keys
   */
  @CanIgnoreReturnValue
  public @Nullable V erase(@Nullable Object rowKey, @Nullable Object columnKey) {
    Integer rowIndex = rowKeyToIndex.get(rowKey);

errors.app.db.already.updated = Es posible que ya haya sido actualizado por otro proceso. Por favor, inténtelo de nuevo.
errors.app.db.already.exists = Los datos ya existen. Por favor, inténtelo de nuevo.
errors.app.double.submit.request = Es posible que esta solicitud ya se haya procesado. Por favor, inténtelo de nuevo.

errors.app.db.already.deleted = Pode ter sido excluído por outro processo. Por favor, tente novamente.
errors.app.db.already.updated = Pode ter sido atualizado por outro processo. Por favor, tente novamente.
errors.app.db.already.exists = Os dados já existem. Por favor, tente novamente.
errors.app.double.submit.request = Esta solicitação pode já ter sido processada. Por favor, tente novamente.

    assertLockHeld()

    if (initialized) {
      return // Already initialized.
    }

    // If a bkp file exists, use it instead.
    if (fileSystem.exists(journalFileBackup)) {
      // If journal file also exists just delete backup file.
      if (fileSystem.exists(journalFile)) {
        fileSystem.delete(journalFileBackup)
      } else {
        fileSystem.atomicMove(journalFileBackup, journalFile)

    public void test_get_nullProperty() {
        // Test getting non-existent property
        try {
            fessConfig.get("non.existent.property");
            fail("Should throw exception for non-existent property");
        } catch (ConfigPropertyNotFoundException e) {
            // Expected exception
            assertTrue(e.getMessage().contains("non.existent.property"));
        }
    }

        // Test with property that doesn't exist and default value
        cmdList.clear();
        execJob.testAddSystemProperty(cmdList, "non.existent.property", "default.value", null);
        assertEquals(1, cmdList.size());
        assertEquals("-Dnon.existent.property=default.value", cmdList.get(0));

        // Test with property that doesn't exist and no default value
        cmdList.clear();