Which two statements are correct regarding Spring Boot 2.x Actuator Metrics? (Choose two.)

Question

Options

• AAn external monitoring system must be used with Actuator.
• BThe metrics endpoint /actuator/metrics is exposed over HTTP by default.
• CTimer measures both the number of timed events and the total time of all events timed.
• DCustom metrics can be measured using Meter primitives such as Counter, Gauge, Timer, and
• EA metric must be created with one or more tags.

• A
  3% (1)
• B
  8% (3)
• C
  75% (30)
• E
  15% (6)

Explanation

C is correct because a Timer in Micrometer (Spring Boot's metrics facade) records both the count of events and the total duration, making it ideal for tracking latency and throughput simultaneously - for example, measuring how many HTTP requests were made and how long they collectively took.

D is correct because Micrometer exposes four core Meter primitives - Counter (monotonically increasing count), Gauge (current value snapshot), Timer (count + duration), and DistributionSummary - which developers use to instrument custom application metrics.

Why the distractors are wrong:

• A is false - Actuator can expose metrics via its own /actuator/metrics HTTP endpoint without any external system; external systems (Prometheus, Datadog, etc.) are optional enhancements.
• B is false - in Spring Boot 2.x, only /actuator/health and /actuator/info are exposed over HTTP by default; /actuator/metrics must be explicitly enabled via management.endpoints.web.exposure.include.
• E is false - tags are optional metadata for dimensional filtering; a metric can be created with zero tags.

Memory tip: Think "C = Count + Clock" (Timer counts events AND clocks their duration), and "D = Do-it-yourself metrics" using the four Meter types. For B, remember the "2 by default" rule: only 2 endpoints (health + info) are HTTP-exposed out of the box.

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