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Comment by gf000 | Hacker News Reader

Could you expand on "how bad the performance can be" part?

If you are doing graphics, it is entirely more likely that you do something dumb there - there are many pitfalls.

Also, unless you are doing something very CPU-heavy, there won't be any noticeable difference as web servers are doing IO predominantly. Maybe slightly less RAM usage (but you could also just decrease the heapsize to tradeoff a bit of CPU-time for memory, if it were to make sense).

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In my game loop I was using optional. When I profiled it the use of optional was one of the slowest points that could be optimized using null checks and ifs.

There were a lot of other slow areas as well, not where you would expect it.

Sure, Optional is not the most optimal thing to use/do, though depending on how many entities you were operating with, that itself may still be negligible.

That’s the pain point - well written java code may not be the most performant depending on the situation.

It wasn’t just optional but other areas as well.

That's not my experience, though game development is certainly a niche and Java may not be the top choice for that.

You might sometimes have to reach for SoA-like structures and reference them via indices, at least for the core ECS, but for the rest you can easily use bog-standard Java -- not everything has to be "ultra-fast, specially written java", just certain hot loops.

Right. I didn’t started digging into it until I realized the application was clearly sluggish in certain scenarios. As I am doing this for fun I am going to see what kind of speed up I get in rust for this.

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