AOP or whatever
AOP is good for security because it separates. Nothing new here, it is an age old paradigm to separate and to reuse. Now you can reuse tested methods, used to be functions/procedures before the new names and acronyms were invented. And if done right that's all you can use until a new is needed, tested, authorized to libraries/objects/what ever. AOP (IMHO) makes life easier except maybe to the persons writing the methods who have to make sure they are safe and work but that's how it has always been so, again, nothing new here. And it is not Java only, AOP can be done on any language, don't restrict yourself. have fun.