public MediaType getContentType() {
        if (isNull(this.contentType)) {
            contentType = getHeader(HeaderName.CONTENT_TYPE)
                .map(MediaType::of)
                .orElse(WILDCARD);
        }

        return contentType;
    }
public MediaType getContentType ( ) { if ( isNull ( this . contentType ) ) { contentType = getHeader ( HeaderName . CONTENT_TYPE ) . map ( MediaType :: of ) . orElse ( WILDCARD ) ; } return contentType ; }
Returns a content-type header value

@return content-type header value in {@link Optional} object