public Collection<V> values() {
      assertTrue(Thread.holdsLock(mutex));
      /* TODO: verify that the Collection is also synchronized? */
      return delegate.values();
    }

    @Override
    public Set<Cell<R, C, V>> cellSet() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.cellSet();
    }

    @Override
    public Map<R, V> column(C columnKey) {
      assertTrue(Thread.holdsLock(mutex));

 * methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change the
 * behavior of {@link #offer} which can lead to unexpected behavior. In this case, you should
 * override {@code offer} as well, either providing your own implementation, or delegating to the
 * provided {@code standardOffer} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

 * to the methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change
 * the behaviour of {@link #offer} which can lead to unexpected behaviour. In this case, you should
 * override {@code offer} as well, either providing your own implementation, or delegating to the
 * provided {@code standardOffer} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

          /*
           * And at least one of the classes inside TypeTokenTest ends up with a null value in
           * TypeMappingIntrospector.mappings. That happens only under older JDKs, too, so it may
           * well be a JDK bug.
           */
          || info.getName().contains("TypeTokenTest")
      /*
       * Luckily, we don't care about analyzing tests at all. We'd skip them all if we could do so

          /*
           * And at least one of the classes inside TypeTokenTest ends up with a null value in
           * TypeMappingIntrospector.mappings. That happens only under older JDKs, too, so it may
           * well be a JDK bug.
           */
          || info.getName().contains("TypeTokenTest")
      /*
       * Luckily, we don't care about analyzing tests at all. We'd skip them all if we could do so

  /**
   * Returns a new thread-safe interner which retains a weak reference to each instance it has
   * interned, and so does not prevent these instances from being garbage-collected. This most
   * likely does not perform as well as {@link #newStrongInterner}, but is the best alternative when
   * the memory usage of that implementation is unacceptable.
   */
  @GwtIncompatible("java.lang.ref.WeakReference")

 * 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.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

 * #add(Object, int)} alone <b>will not</b> change the behavior of {@link #add(Object)}, which can
 * lead to unexpected behavior. In this case, you should override {@code add(Object)} as well,
 * either providing your own implementation, or delegating to the provided {@code standardAdd}
 * method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

 * the methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change
 * the behavior of {@link #addAll}, which can lead to unexpected behavior. In this case, you should
 * override {@code addAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardAddAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

 * methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change the
 * behavior of {@link #addAll}, which can lead to unexpected behavior. In this case, you should
 * override {@code addAll} as well, either providing your own implementation, or delegating to the
 * provided {@code standardAddAll} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code