Comment by ardel95

I'm glad folks are starting to look at memory efficiency of Java programs - there's just so much improvements to be had there. For a fun exercise, take a look at memory footprint of storing a million entries in a HashMap<Integer, Integer>. Between "object header" overhead, "everything is a pointer to a heap allocated object" overhead, "GC needs enough headroom to remain effective" overhead, the actual memory consumption can be as much as 10x of a comparable C, C++, or Rust implementation.