Explore the intricacies of bytecode costs in this 37-minute conference talk by Duncan MacGregor at the JVM Language Summit 2016. Delve into the world of SmallWorld and Magic, examining various approaches to bytecode optimization. Learn about facilities, optimistic approaches, AST and IR interpreters, and time costs associated with bytecode execution. Analyze what went wrong in certain optimization attempts, and understand the importance of opportunity costs and class hierarchy analysis. Discover the impact of inlining on performance through benchmark discussions, gaining valuable insights into Java bytecode optimization techniques.