public @Nullable V put(K key, V value) {
      assertTrue(Thread.holdsLock(mutex));
      return super.put(key, value);
    }

    @Override
    public void putAll(Map<? extends K, ? extends V> map) {
      assertTrue(Thread.holdsLock(mutex));
      super.putAll(map);
    }

    @Override
    public Set<K> keySet() {
      assertTrue(Thread.holdsLock(mutex));
      return super.keySet();
    }

  }

  /** @since 11.0 */
  @Override
  public void put(K key, V value) {
    delegate().put(key, value);
  }

  /** @since 12.0 */
  @Override
  public void putAll(Map<? extends K, ? extends V> m) {
    delegate().putAll(m);
  }

  @Override
  public void invalidate(Object key) {
    delegate().invalidate(key);
  }

  /** @since 11.0 */
  @Override

            synchronized (systemProperties) { // avoid concurrent modification if someone else sets/removes an unrelated
                // system property
                this.systemProperties.putAll(systemProperties);
            }
        } else {
            this.systemProperties = null;
        }

        return this;
    }

    @Override
    public Properties getUserProperties() {

        final Map<String, Object> sourceMap = new HashMap<>();
        if (name != null) {
            sourceMap.put("name", name);
        }
        if (attributes != null) {
            sourceMap.putAll(attributes);
        }
        return sourceMap;
    }

   * {@code put()} or {@code putAll()}, or {@code setValue()} on its entries.
   *
   * <p>In contrast, the maps returned by {@code rowMap().get()} have the same behavior as those
   * returned by {@link #row}. Those maps may support {@code setValue()}, {@code put()}, and {@code
   * putAll()}.
   *
   * @return a map view from each row key to a secondary map from column keys to values

        } else if (targetLocations == null) {
            locations = sourceLocations;
        } else {
            locations = new LinkedHashMap<>();
            locations.putAll(sourceDominant ? targetLocations : sourceLocations);
            locations.putAll(sourceDominant ? sourceLocations : targetLocations);
        }

        return new InputLocation(-1, -1, InputSource.merge(source.getSource(), target.getSource()), locations);

                    ImmutableSetMultimap<String, Integer> badEntries =
                        ImmutableSetMultimap.of("foo", 314, "one", 159, "two", 265, "bar", 358);
                    multimap.putAll(badEntries);
                    return Multimaps.filterEntries(
                        multimap, not(Predicates.in(badEntries.entries())));
                  }
                })

    @Override
    public void putAll(RangeMap<K, ? extends V> rangeMap) {
      if (rangeMap.asMapOfRanges().isEmpty()) {
        return;
      }
      Range<K> span = rangeMap.span();
      checkArgument(
          subRange.encloses(span),
          "Cannot putAll rangeMap with span %s into a subRangeMap(%s)",
          span,
          subRange);
      TreeRangeMap.this.putAll(rangeMap);
    }

    @Override

 * the methods of the delegate. For example, overriding {@link #put} alone <i>will not</i> change
 * the behavior of {@link #putAll}, which can lead to unexpected behavior. In this case, you should
 * override {@code putAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardPutAll} method.
 *

    filtered.put("a", 1);
    filtered.put("b", 2);
    assertEquals(ImmutableMap.of("a", 1, "b", 2), filtered);

    assertThrows(
        IllegalArgumentException.class,
        () -> filtered.putAll(ImmutableMap.of("c", 3, "zzz", 4, "b", 5)));

    assertEquals(ImmutableMap.of("a", 1, "b", 2), filtered);
  }

  public void testFilteredKeysFilteredReflectsBackingChanges() {