public class TraceAdvice implements MethodInterceptor {    private static final Log log = LogFactory.getLog(TraceAdvice.class);    public Object invoke(MethodInvocation invocation) throws Throwable {       String methodName = invocation.getMethod().getName();       String className = invocation.getThis().getClass().getName();       log.trace("*** Start : " + methodName + " of class [" + className + "]");       Object ret = invocation.proceed();       log.trace("*** End : " + methodName + "' of class [" + className + "]");          return ret;    } }