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LetsGit.IT/Categories/Kotlin
Kotlinhard

Job vs SupervisorJob — how do failures propagate?

Tags
#coroutines#job#supervisorjob#cancellation
Back to categoryPractice quiz

Answer

With a regular Job, a child failure cancels the parent and usually the whole scope. With SupervisorJob (supervisor scope), a failing child doesn’t cancel siblings; you handle the failure locally.

Advanced answer

Deep dive

Expanding on the short answer — what usually matters in practice:

  • Context (tags): coroutines, job, supervisorjob, cancellation
  • JVM: memory (heap/stack), GC, and what drives latency.
  • Contracts: equals/hashCode/toString, mutability and consequences.
  • Performance: boxing, allocations, collections, inlining.
  • Explain the "why", not just the "what" (intuition + consequences).
  • Trade-offs: what you gain/lose (time, memory, complexity, risk).
  • Edge cases: empty inputs, large inputs, invalid inputs, concurrency.

Examples

A tiny example (an explanation template):

// Example: discuss trade-offs for "job-vs-supervisorjob-—-how-do-failures-propagate"
function explain() {
  // Start from the core idea:
  // With a regular Job, a child failure cancels the parent and usually the whole scope. With S
}

Common pitfalls

  • Too generic: no concrete trade-offs or examples.
  • Mixing average-case and worst-case (e.g., complexity).
  • Ignoring constraints: memory, concurrency, network/disk costs.

Interview follow-ups

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