public ImmutableList<String> getDocComment() {
    if (docComment == null) {
      this.docComment = constitution.isImplementationPrimary()
          || style().getStyles().isImmutableIdentityNaming()
          ? extractDocComment(element)
          : ImmutableList.<String>of();
    }
    return docComment;
  }
Means object hashcode is cached at some point. Either lazily (on first access)
or eagerly (during construction).
@see #isUseLazyhash()
@see #isUsePrehashed()
value-processor/src/org/immutables/value/processor/meta/ValueType.java