Yes, they are. I have learned a number of technologies through the years, but I have never run into a system that is imposible to implement until now.
Servlets and JSP's are a snap. I picked them up quickly and was writing apps fast.
But EJB's, I struggled to get session beans to work, but I did it. But entity and MDB's...they are the Devil's brew. I hate it when I follow the directions and it STILL doesn't work. Deployment is such a mess. I am thinking of giving up and sticking to Servlets.