Follow-up · depth 1
What metrics prove CompletableFuture Composition is healthy in prod?
What metrics prove CompletableFuture Composition is healthy in prod?
Answers use simple, clear English.
Quick interview answer
Prove CompletableFuture Composition is healthy with latency (p50/p95/p99), error/saturation rates, and queue/event-loop lag — not just CPU. Context: Logic: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Detailed answer
Production health signals for CompletableFuture Composition: • Latency: p50/p95/p99 of the critical path that uses CompletableFuture Composition. • Errors: failure rate, timeouts, and retry storms. • Saturation: queue depth, event-loop delay, thread/pool utilization. • Business SLIs: request success and user-visible freshness where relevant. Trade-off lens: Pros: Composable async without raw callbacks; integrates with thread pools. Cons: Default ForkJoinPool.commonPool() shared — inject Executor for isolation. Explain thresholds + alerts, then how you triage. Parent context: Logic: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Full explanation
Good answers name measurable signals and what “bad” looks like for CompletableFuture Composition. supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
Follow-up questions
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Parent context — CompletableFuture Composition
Logic: supplyAsync runs async task; thenApply transforms; thenCompose flattens nested futures; allOf waits for batch. Exceptionally/handle for error paths.
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