"jcmd will now be able to alter some fine-grained JIT compiler directives at runtime and you can define them statically at startup; this may be particularly useful for those low latency applications with warmup concerns"
"JEP 269, available in Java 9, adds factory methods for collections which return immutable collections, eg List.of(a, b, c, ...), Map.of(k1, v1, k2, v2, ...). Note that immutable collections are automatically threadsafe. They are also space efficient."
