String value1 = fessConfig.get(testKey);
            assertEquals(initialValue, value1);

            // Change system property
            String newValue = "changed";
            System.setProperty(Constants.FESS_CONFIG_PREFIX + testKey, newValue);

            // Get value again - in real FessConfigImpl it would be cached,
            // but our test implementation always checks system properties

        }

        @Override
        public boolean remove(Object key, Object value) {
            throw uoe();
        }

        @Override
        public boolean replace(K key, V oldValue, V newValue) {
            throw uoe();
        }

        @Override
        public V replace(K key, V value) {
            throw uoe();
        }

        @Override

   */
  final void checkNoDuplicate(R rowKey, C columnKey, @Nullable V existingValue, V newValue) {
    checkArgument(
        existingValue == null,
        "Duplicate key: (row=%s, column=%s), values: [%s, %s].",
        rowKey,
        columnKey,
        newValue,
        existingValue);
  }

  // redeclare to satisfy our test for b/310253115
  @Override
  @J2ktIncompatible

     *
     * @param key the key under which to store the session data, must not be {@code null}
     * @param oldValue the expected data currently associated with the key, may be {@code null}
     * @param newValue the data to associate with the key, may be {@code null} to remove the mapping
     * @return {@code true} if the key mapping was successfully updated from the old value to the new value,

    Integer oldValue = map.putInstance(Integer.class, Integer.valueOf(7));
    assertEquals(5, (int) oldValue);

    Integer newValue = map.getInstance(Integer.class);
    assertEquals(7, (int) newValue);
    assertEquals(7, (int) map.getInstance(TypeToken.of(Integer.class)));

    // Won't compile: map.putInstance(Double.class, new Long(42));
  }

  public void testNull() {

   */
  private void replaceValueInEntry(int entry, @ParametricNullness V newValue, boolean force) {
    checkArgument(entry != ABSENT);
    int newValueHash = Hashing.smearedHash(newValue);
    int newValueIndex = findEntryByValue(newValue, newValueHash);
    if (newValueIndex != ABSENT) {
      if (force) {
        removeEntryValueHashKnown(newValueIndex, newValueHash);

 *     }
 *     V result = value;
 *     value = null;
 *     notifyAll();
 *     return result;
 *   }
 *
 *   public synchronized void set(V newValue) throws InterruptedException {
 *     while (value != null) {
 *       wait();
 *     }
 *     value = newValue;
 *     notifyAll();
 *   }
 * }
 * }
 *
 * <h3>{@code ReentrantLock}</h3>
 *

    public void test_overwriteValues() {
        dataStoreParams.put("key1", "originalValue");
        assertEquals("originalValue", dataStoreParams.get("key1"));

        dataStoreParams.put("key1", "newValue");
        assertEquals("newValue", dataStoreParams.get("key1"));

        dataStoreParams.put("key1", null);
        assertNull(dataStoreParams.get("key1"));
    }

    // Test multiple operations in sequence

        return requestBody;
    }

    @Override
    protected Map<String, Object> getUpdateMap() {
        final Map<String, Object> updateMap = new HashMap<>();
        updateMap.put("value", "newValue");
        return updateMap;
    }

    @Test
    void crudTest() {
        testCreate();
        testRead();
        testUpdate();
        testDelete();
    }

   *
   * @param currentValue the current value (of either base or a cell)
   * @param newValue the argument from a user update call
   * @return result of the update function
   */
  abstract long fn(long currentValue, long newValue);

  /**
   * Handles cases of updates involving initialization, resizing, creating new Cells, and/or