code: public static void assertBodyNotPresent(String msg, SipMessage sipMessage) {
      assertNotNull("Null assert object passed in", sipMessage);
      assertFalse(msg, sipMessage.getContentLength() > 0);
    }
docs: Asserts that the given SIP message contains no body. Assertion failure output includes the
  given message text.
  
  @param msg message text to output if the assertion fails.
  @param sipMessage the SIP message.