code: public void removeAttribute(String name) {
  		if(logger.isDebugEnabled()) {
          	logger.debug("removeAttribute - name=" + name);
          }
  		if(attributes  != null) {
  			this.attributes.remove(name);
  		}
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipServletMessage#removeAttribute(java.lang.String)