AOP for performance monitoring in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an aspect class for performance monitoring.

Spring Boot

import org.aspectj.lang.annotation.[1];

@Aspect
public class PerformanceAspect {

}

Drag options to blanks, or click blank then click option'

AAspect

BComponent

CService

DRepository

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component instead of @Aspect

Forgetting to import the annotation

Confusing @Service with @Aspect

The @Aspect annotation marks the class as an aspect for AOP.

2fill in blank

medium

Complete the code to define a pointcut expression that matches all methods in the service package.

Spring Boot

@Pointcut("execution(* com.example.service..*[1]*(..))")
public void serviceMethods() {}

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A+

B.

C*

D#

Attempts:

3 left

💡 Hint

Common Mistakes

Using '.' instead of '*' for method names

Using '+' which is for class inheritance

Using '#' which is not valid here

The * wildcard matches any method name in the specified package.

3fill in blank

hard

Fix the error in the advice method to correctly measure execution time.

Spring Boot

@Around("serviceMethods()")
public Object measureTime(ProceedingJoinPoint joinPoint) throws Throwable {
    long start = System.currentTimeMillis();
    Object result = joinPoint.[1]();
    long end = System.currentTimeMillis();
    System.out.println("Execution time: " + (end - start) + " ms");
    return result;
}

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Aexecute

Bproceed

Crun

Dcall

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'execute' which does not exist

Using 'run' which is unrelated

Using 'call' which is invalid here

The proceed() method executes the target method and returns its result.

4fill in blank

hard

Fill both blanks to log the method name and execution time inside the advice.

Spring Boot

String methodName = joinPoint.getSignature().[1]();
System.out.println("Method " + methodName + " took " + [2] + " ms");

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AgetName

Bend - start

CgetClassName

Dstart - end

Attempts:

3 left

💡 Hint

Common Mistakes

Using getClassName instead of getName

Subtracting times in wrong order

Printing variables before they are defined

getName() gets the method name. The difference end - start gives execution time.

5fill in blank

hard

Fill all three blanks to create a complete around advice that measures and logs execution time for service methods.

Spring Boot

@Around("[1]")
public Object logExecutionTime(ProceedingJoinPoint joinPoint) throws Throwable {
    long [2] = System.currentTimeMillis();
    Object result = joinPoint.proceed();
    long [3] = System.currentTimeMillis();
    System.out.println("Execution time: " + (end - start) + " ms");
    return result;
}

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AserviceMethods()

Bstart

Cend

Dexecution(* com.example.repository..*(..))

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong pointcut expression

Mixing up start and end variable names

Forgetting to call proceed()

The pointcut serviceMethods() targets service methods. Variables start and end store timestamps before and after method execution.