code: public static void agentmain(String agentArgs, Instrumentation instrumentation) {
          JvmAgentConfig config = new JvmAgentConfig(agentArgs);
          if (!config.isModeStop()) {
              startAgent(config,false, instrumentation);
          } else {
              stopAgent();
          }
      }
docs: Entry point for the agent, using dynamic attach
  (this is post VM initialisation attachment, via com.sun.attach)
  
  @param agentArgs arguments as given on the command line