code: public ResponseBuilder initialize(final Resource parent, final Resource child) {
          if (MISSING_RESOURCE.equals(parent)) {
              // Can't POST to a missing resource
              throw new NotFoundException();
          } else if (DELETED_RESOURCE.equals(parent)) {
              // Can't POST to a deleted resource
              throw new ClientErrorException(GONE);
          } else if (ACL.equals(getRequest().getExt())
                  || ldpResourceTypes(parent.getInteractionModel()).noneMatch(LDP.Container::equals)) {
              // Can't POST to an ACL resource or non-Container
              throw new NotAllowedException(GET, Stream.of(HEAD, OPTIONS, PATCH, PUT, DELETE).toArray(String[]::new));
          } else if (!MISSING_RESOURCE.equals(child) && !DELETED_RESOURCE.equals(child)) {
              throw new ClientErrorException(CONFLICT);
          } else if (!supportsInteractionModel(ldpType)) {
              throw new BadRequestException("Unsupported interaction model provided", status(BAD_REQUEST)
                  .link(UnsupportedInteractionModel.getIRIString(), LDP.constrainedBy.getIRIString()).build());
          } else if (ldpType.equals(LDP.NonRDFSource) && rdfSyntax != null) {
              LOGGER.error("Cannot save {} as a NonRDFSource with RDF syntax", getIdentifier());
              throw new BadRequestException("Cannot save resource as a NonRDFSource with RDF syntax");
          }
  
          setParent(parent);
          return status(CREATED);
      }
docs: Initialize the response.
  @param parent the parent resource
  @param child the child resource
  @return a response builder