Java is a good language for someone who is just a beginner of learning program, but it dose not suit to making game because its high level and low performance.
The creators of Minecraft, RuneScape, Puzzle Pirates and Wurm Online (amongst others) would probably disagree... Java is just fine for games, and whilst it isn't for everyone there's absolutely no reason to spread nonsense about it being "not suited to making games". The fact that it's higher level is potentially a good thing (as has already been covered at length in this topic), and while there can be some additional performance concerns the idea that it's "too slow" for games is largely just out-dated and no-longer relevant.