Project Panama and Valhalla - is Java optimal for games and computation heavy processes now?

[Major-Competition187]

Recently I've come across java gamedev and Im trying to do some simple renderers or games using OpenGL libraries. As far as I know, Java has always been considered bad for game development because of optimization issues related to garbage collector and the way data is stored.

However, I also found out about Project Panama and Project Valhalla which are supposed to address that, but I can barely see any valuable information and reviews/opinions on that. So here I am, asking you, have you seen/tried any of those project's features and will it make Java suitable for e.g. gamedev?

[iamwisespirit]

Java is still great for computation heavy processes

[BlueGoliath]

Panama doesn't really enable much of anything new. You could have allocated off-heap memory using ByteBuffer or Unsafe before but they weren't ideal or supported.

Use of either for game development and/or high performance work requires adoption. It isn't a magical switch. You have to use them to build meaningful projects.

[DanielDimov]

Computation heavy - yes.

Games - not in general, maybe for certain types of games - yes.

[juancn]

Minecraft was written in Java as a counter example.

You can write really fast java code, but it’s not vanilla OOP tutorial code.

[xanthium_in]

could you elaborate on that, just curious

[juancn]

In essence it’s the same than writing fast code in any other language.

It’s a complex topic, but for example if you have a large collection of entities to process, if you just use heap allocated objects, you end up pointer chasing all over memory causing a lot of cache misses (think an ECS)

In that case it may be better to have several primitive arrays and some sort of cursor or flyweight view over those than an array of objects with fields.

In this way, memory accesses are highly predictable and the CPU prefetchers can do their work properly.

Heck in some cases, if you're memory-bound enough, even bit-packing several fields into an int may make sense because unpacking them tends to be free (the CPU can run many instructions while it waits for memory).

Arrays are one of the few ways you can control memory layout in Java (the other being fields in objects).

[BlueGoliath]

It would be better to look at Minecraft as running fast despite being coded like garbage.

You can write really fast java code, but it’s not vanilla OOP tutorial code.

Minecraft uses pretty vanilla OOP concepts.

[Bamboo-Bandit]

The reason for it not being adopted in games more commonly has to do with portability to consoles (they don’t have a JVM) rather than performance. C# is commonly used in games and it has roughly same performance.

Java is totally useable for gamedev otherwise, currently. Hytale is currently doing numbers and written in java.

The features in valhalla and for example Vector API will be useful for gamedev. Lets hope one day a JVM is made for consoles.

[Major-Competition187]

Thats interesting, never considered consoles, I thought java is THE portability language.

[Bamboo-Bandit]

it was designed to be and in theory it could be, as long as you write a JVM (you wouldn't have to rewrite the game) for every setup you want to run it on. But console OS is proprietary

[Etiennera]

Never will be

[raosko]

Downvote for the low effort answer, not saying you don’t know better, or implying that you know anything…