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Spring / Resilience4j Interview questions

List the key configuration properties of a CircuitBreaker?
  • failureRateThreshold - percentage of failed calls that trips the breaker to OPEN.
  • slowCallRateThreshold / slowCallDurationThreshold - treat calls slower than a duration as failures too.
  • slidingWindowType / slidingWindowSize - COUNT_BASED or TIME_BASED window used to compute the rate.
  • minimumNumberOfCalls - minimum calls recorded before the failure rate is even evaluated.
  • waitDurationInOpenState - how long the breaker stays OPEN before trying HALF_OPEN.
  • permittedNumberOfCallsInHalfOpenState - trial calls allowed while HALF_OPEN.
  • recordExceptions / ignoreExceptions - which thrown exceptions count as failures.

These are typically set per named instance under resilience4j.circuitbreaker.instances.<name> in application.yml, or programmatically via CircuitBreakerConfig.custom().

Which property sets the minimum number of recorded calls before failure rate is evaluated?
slowCallDurationThreshold is used to:

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