title: how can spring get args name from the method
body: <p>In spring, it express the arg-names like this : </p>
  
  <pre><code>@Before(
  value="com.xyz.lib.Pointcuts.anyPublicMethod() &amp;&amp; target(bean) &amp;&amp; @annotation(auditable)",
  argNames="bean,auditable")
  public void audit(JoinPoint jp, Object bean, Auditable auditable) {
      AuditCode code = auditable.value();
  // ... use code, bean, and jp
  }
  </code></pre>
  
  <p>In the doc , it says you may leave out the name of the parameter from the value of the "argNames" attribute. How can spring get argNames("bean,auditable") from anyPublicMethod?</p>
  
  <p>Did java provide some api to get the parameter names?</p>
  
  <p>I think it use the aspectJ to parse the expression, did aspectJ provide the feature?</p>