Reinforcement learning isn't just for games or chatbots. At Diffblue, it's how our AI learns to write Java unit tests. No labels. No prompts. Just feedback loops that improve coverage and catch regressions. xAI's Grok 4 shows where RL is going. We're already putting it to work. #AI #ReinforcementLearning #Java #UnitTesting #DiffblueCover