code: public Object getAttribute(String name) {
  		if(logger.isDebugEnabled()) {
  			logger.debug("getAttribute - name=" + sessionKey);
  		}
  		if (name == null)
  			throw new NullPointerException("Attribute name can not be null.");
  		return this.getAttributeMap().get(name);
  	}
docs: /*
  (non-Javadoc)
  @see javax.servlet.sip.SipServletMessage#getAttribute(java.lang.String)