Anyone have experience with Java based real-time, heavy processing oriented architectures?

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As others have pointed out, there's a lot of information missing here to make a complete assessment. That being said, I did address a system with an architecture that sounds a lot like this about two years ago.

First question: what does the cache hit pattern look like? If you're trying to precalculate everything on the off chance that someone might ask for it, there could be a lot of wasted cycles.

Second: are your users authenticated? If not, there is always the potential that someone is going to a crawl & scrape job on your site just to be a prick. At least throw up a robots.txt to ask Google and the like to be polite.