Peter Lawrey discusses Unsafe in Java 8, Project Panama in Java 17 and Java 19, including pactical uses with code examples, demo using Panama, Event Sourcing using shared memory with Chronicle Queue.

Want a heap dump? Check out the jmap (Java memory map) and jhat (Java heap analysis tool) shipped with Hotspot-based JVMs (Sun, OpenJDK). Looking for a bit more?

The Java Memory Map (JMAP) utility has a method that prints a histogram of the Java heap. One side effect of the jmap command is that when it's called, it forces a garbage collection routine.