Azul vega supermachine

Azul Vega™ 3 7300 and 3300 Series.
"...with up to 864 processor cores and 768 GB of memory in a flat SMP configuration."
"...are built around the Vega 3 processor, the first 54-core chip designed and optimized for Java workloads."

And only 14U, so not very big box.