Primitive-Collections VS Agrona

In some places I'm using https://github.com/aeron-io/agrona

Strangely this is one of the areas where I want to use project panama so I might re-implement some of the ring buffers constructs.

You allocate off heap memory and dump data into it. With modern Java classes like Arena, MemoryLayout, and VarHandle it's honestly a lot like C structs.

I answered "why" in another post in this thread.

Thanks, I've mostly used fastutil lately because it seems to be best maintained. I'll have to look at carrotlabs though, I like the approach of a clean break with java.util.collections.*.

The Agrona Java library from the Aeron people has some primitive optimized collections too: https://github.com/aeron-io/agrona

Aeron for low latency apps and Agrona is you're using Aeron for data structures

Martin Thompson is one of the leaders in that space: his blog is a really great place to start. His Agrona library is a bunch of high-performance data structures, which you can use directly, but which can also serve as examples of writing such code.

ByteBuffer methods have quite a bit of overhead. You could further try to (1) writing to a byte[] first and then using the put(byte[]) method, or (2) use sun.misc.Unsafe::putByte (maybe try with Agrona's DirectBuffer and copy the necessary lines if need be).