code: public static boolean sameLiteral(Literal l1, Literal l2) {
          URI type = l2.getDatatypeURI();
          return sameLiteral(l1, l2.getLexicalForm(), type, l2.getLanguage());
      }
docs: Tells whether the given literals are equivalent.
  <p>
  Two literals are equivalent if they have the same lexical value, language
  (which may be unspecified), and datatype (which may be unspecified).
  
  @param l1
  first literal.
  @param l2
  second literal.
  @return true if equivalent, false otherwise.