How to Write Bad Java Code, by Pratik Patel

A lightning talk covering common Java performance pitfalls, many of which can be introduced by AI code assistants. Topics include: string concatenation vs StringBuilder (O(n²) vs efficient), avoiding the 'pyramid of doom' with Optional for null checks, boxing/unboxing overhead in loops, compiling regex patterns only once outside loops, minimizing method calls in hot paths, and avoiding unnecessary synchronization. The JIT compiler handles some of these automatically (method inlining, loop invariant hoisting), but others like string concatenation and regex compilation require manual fixes.