Properly manage executor service lifecycle to prevent resource leaks, deadlocks, and orphaned threads that can cause system inconsistencies. Key practices: 1. **Use try-with-resources**: Always manage executors within try-with-resources blocks to ensure proper shutdown 2. **Avoid manual future cancellation**: Prefer structured concurrency patterns like `invokeAny()` over low-level `submit().get()` with manual cancellation 3. **Prevent orphaned threads**: Ensure worker threads are properly joined before allowing new operations to proceed 4. **Choose appropriate synchronization**: Use higher-level primitives like `Phaser` instead of combining multiple lower-level mechanisms Example of proper executor management: ```java try (var executor = Executors.newSingleThreadExecutor(threadFactory)) { // Submit tasks and get results within the try block var future = executor.submit(callable); return future.get(timeout, TimeUnit.SECONDS); } // Executor automatically shuts down here ``` For cancellation scenarios, prefer structured approaches: ```java // Instead of manual future cancellation var future = executor.submit(task); future.cancel(true); // Use invokeAny for timeout/cancellation semantics return executor.invokeAny(List.of(task), timeout, TimeUnit.SECONDS); ``` This prevents common issues like deadlocks when futures are never scheduled, ensures proper resource cleanup, and avoids race conditions from orphaned threads modifying shared state after new operations have begun.