I didn’t take your post as an attack, I simply didn’t understand it as I see that there is quite a lot of knowledge readily available and AFAIC this thread mostly proved a commonly known best practice regarding GC. I just didn’t understand why you see this as a sign of immaturity.
There are a number of good books for games (I only read Andrew Davison’s book but though it was quite good, but I hear there are more good ones), there is Jeff’s Performance Tuning book (a bit outdated, but still very useful), there is this site, and there’s probably a lot more available too.
But, like I said, compared to C++, of course java is not as mature for gaming. As I see it, this is to be expected, and there’s more to it than just C++ vs. java: The fact that VM technology is so rapidly evolving, some ‘best practices’ are bound to change a lot. For example, object pooling used to be a common good practice to avoid GC stutter. Not so anymore. On the old MS VM, inlining code manually or otherwise uglyfying your code (like using fixed point calculations instead of the now quite fast floats) was needed to squeeze performance out of it. On recent VM’s this can even make performance worse. And let’s not even start about J2ME, where things are very different.
Maybe this confusion is where your feeling of immaturity comes from. If so, you do have a point. This community is probably where you will learn the most because, as Cas said, many experienced people come here and even the Sun folks come here to keep us updated and clear up confusion.
And you’ll be happy to learn that flame wars don’t happen here often. 
