How change java code on runtime by MethodInterceptor

I want modify my code on runtime by @annotation and interceptor. I created a simple example to explain my need on the stackoverflow website.

How change i = i + 1; to i = i + 3; on runtime (in my invoke of MyRetryInterceptor).

My original (public) code:

@MyRetry(value = 3)
public void testforRetry() {
    int i = 0;
    logger.info("testforRetry " + i);
    i = i + 1;
    logger.info("testforRetry " + i);
}

My Method Interceptor:

public class MyRetryInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Method m = invocation.getMethod();
        Object result = invocation.proceed();
        return result;
    }
}