Explore VM design choices in this comprehensive talk from the 2015 JVM Language Summit. Delve into interpreter options, optimization strategies, garbage collection approaches, and multithreading considerations. Learn about atomic operations, native calls, safe points, debugging flags, and the Java Memory Model. Examine topics like inline caching, HotSpot, Azul, thread-local storage, and transactional memory. Gain insights into safepoints, adapter frames, inlining constant OOPs, and object locking as presented by Cliff Click, offering valuable knowledge for language designers, compiler writers, tool builders, runtime engineers, and VM architects.