Spring | Hibernate | Transaction management with AspectJ

Question

We are working on a new project using Spring, Hibernate and Transaction management using AspectJ (@Transactional annotations) and we are not sure what is the best practices weaving options to go.

We've started with the LTW and placed the tomcat Loader, it worked fine.. but then we thought that it may be less risky to have compile time weaving which instruments and *.classes and not on load time (in memory), so it will done just one time and not when on the tomcat startup. This is done via Maven aspectj-maven-plugin plugin.

Can you please advice ? What are the pros and cons of using those weaving options ?

Thanks!

Answer 1

Disclaimer: This is not a discussion forum but a Q/A platform, so your question does not have the correct answer, it rather sparks discussion. I am trying to elaborate a bit anyway.

You basically already stated the main facts about LTW versus CTW. I am failing to see why LTW should be more risky than CTW, though. It slows down your server start-up, but the risk is the same as with CTW because the resulting byte code is also the same. Or are you talking about the risk that maybe more code gets (eg 3rd party libraries) woven than you intend? In that case yet, CTW keeps you on the safe side and you have more control over what should be woven. It should also speed up your server start-up time in comparison with LTW.

So if you have no compelling reasons to use LTW, such as the wish to dynamically intercept code you are unaware of during development, go ahead and use CTW and you are on the safe side, as long as you are fine with adjusting your build process accordingly. AspectJ Maven plugin is pretty straightforward to use, so that should not be a big deal. You can still switch to LTW as needed and when needed. OTOH, if you are using LTW now and are fine with the server start-up time, maybe there is no need to switch. If unsure, try both approaches and compare the results. ;-)