{CodeRoyale}
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Multiple ChoiceHard 45s

Observer and memory leaks

Event listeners registered on a long-lived publisher are never unregistered, and short-lived subscribers accumulate. What is the classic problem and fix?
Options
  1. 1Observer is inherently unsafe; replace it with polling
  2. 2The publisher must clone every listener on notify to avoid leaks
  3. 3Listeners should be static to avoid garbage collection
  4. 4Lapsed-listener leak; use weak references or explicit unsubscribe on lifecycle end
architecturedesign-patternsobserver

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