Spring Cloud Spring Cloud Circuit Breaker & Resilience 2

Question 1

What is the default sliding window type used by Resilience4j circuit breakers?

Accepted Answer

COUNT_BASED

Answer

Resilience4j defaults to a COUNT_BASED sliding window, which tracks the outcome of the last N calls to compute the failure rate.

Question 2

When does a Resilience4j circuit breaker enter the Half-Open state?

Accepted Answer

After the waitDurationInOpenState has elapsed while the circuit is Open

Answer

After waiting in Open state for waitDurationInOpenState duration, the circuit breaker transitions to Half-Open to allow probe calls and test if the downstream service has recovered.

Question 3

Which Resilience4j configuration property defines how long the circuit remains in Open state before transitioning to Half-Open?

Accepted Answer

waitDurationInOpenState

Answer

waitDurationInOpenState sets the duration the circuit breaker remains in Open state before switching to Half-Open to test recovery.

Question 4

Which Resilience4j pattern limits the number of concurrent calls to a service to isolate failures and prevent resource exhaustion?

Accepted Answer

Bulkhead

Answer

The Bulkhead pattern limits concurrent calls to a service, isolating it so a spike of slow calls cannot exhaust shared resources and affect other services.

Question 5

What does the @RateLimiter annotation control when applied to a method in Resilience4j?

Accepted Answer

The number of calls allowed within a configured time window

Answer

@RateLimiter restricts how many calls can be made to the annotated method within a defined time period, preventing downstream overload.

Spring Cloud Practice Test

Spring Cloud Practice Test

Spring Cloud Spring Cloud Circuit Breaker & Resilience 2