Write a production-quality @Around aspect. What do pointcut expressions look like, and what mistakes do you watch for?

@Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME)
public @interface Timed { String value(); }

@Aspect @Component
public class TimingAspect {
    private final MeterRegistry metrics;
    TimingAspect(MeterRegistry metrics) { this.metrics = metrics; }

    @Around("@annotation(timed)")                 // binds the annotation instance
    public Object time(ProceedingJoinPoint pjp, Timed timed) throws Throwable {
        long t0 = System.nanoTime();
        String outcome = "success";
        try {
            return pjp.proceed();                 // 1. ALWAYS return proceed()'s value
        } catch (Throwable t) {
            outcome = "error";                    // 2. observe, DON'T swallow
            throw t;
        } finally {                               // 3. aspect never throws from here
            metrics.timer(timed.value(), "outcome", outcome)
                   .record(System.nanoTime() - t0, TimeUnit.NANOSECONDS);
        }
    }
}