Clarification needed on AgentBuilder.Transformer.ForAdvice::include()

I’m trying to capture a call coming in through a servlet engine. Here’s my code:

    
    
    @Advice.OnMethodEnter
    public static void enter(final @Advice.AllArguments Object[] args) {
       GenericIngressHandler.enter(args[0], "getHeader");
    }

    @Advice.OnMethodExit
    public static void exit() {
        GenericIngressHandler.exit();
    }

    public static AgentBuilder buildAgent(AgentBuilder b) {
        return b.type(named("javax.servlet.http.HttpServlet"))
                .transform(
                        new AgentBuilder.Transformer.ForAdvice()
                            .include(ServletIngressHandler.class.getClassLoader())
                            .advice(new Matchers.WildcardMethodMatcher(
                        "service(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)"),
                                ServletIngressHandler.class.getName()));
        
    }
}

It fails when it’s trying to load the GenericIngressHandler when executed through the Open Liberty appserver. It seems that it has some custom classloader that doesn’t see my code.

So I added include(ServletIngressHandler.class.getClassLoader()) to the definition of the transformer thinking that it would somehow insert the classloader of my package into the mix. However, it still can’t see the class. Maybe I’m using include() wrong? Some clarification in the documentation would be great!

[raphw]

Any code referenced in your advice classes must be available to the class loader that is executing the advice. The include method only assures that Byte Buddy can see class files provided by class loaders while inlining the advice.

Normally, you add classes that you need to be universally visible to the bootstrap class loader. The Instrumentation interface provides a method for that.

[raphw]

Good to hear, checked your doc and this approach should also allow you avoid - Xbootclassloader.