android/guava/src/com/google/common/collect/ImmutableMultimap.java
@CanIgnoreReturnValue
  @Deprecated
  @Override
  public boolean putAll(K key, Iterable<? extends V> values) {
    throw new UnsupportedOperationException();
  }
@CanIgnoreReturnValue
  @Deprecated
  @Override
  public boolean putAll(K key, Iterable<? extends V> values) {
    throw new UnsupportedOperationException();
  }
Guaranteed to throw an exception and leave the multimap unmodified.

@throws UnsupportedOperationException always
@deprecated Unsupported operation.