Minecraft Java used to allocate over 200MB/s per player when moving, and just 50MB/s when static. A lot of it stems back from Minecraft 1.8, where code was updated to take a BlockPos(float x, float y, float z) class instead of just (float x, float y, float z). Pretty much every single object in the game has to deal with its position. Millions of objects allocated per frame, only to be discarded later. Along with a looooot of other questionable choices. It's not even a runtime problem: you'd have the same issues free()'ing that memory on your own. Just stop allocating so damn much.

But then again, Notch never claimed to be a great programmer.