Follow-up · depth 2
What metrics prove CompletableFuture Composition is healthy in prod?
What metrics prove CompletableFuture Composition is healthy in prod?
Answers use simple, clear English.
Audio N/AQuick 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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