Q1. How would you implement logging using AOP in a Spring project?
Create an aspect class annotated with
Define a pointcut for all service methods, and a
Example:
@Aspect and @Component.Define a pointcut for all service methods, and a
@Before advice to log method entry.Example:
@Aspect
@Component
public class LoggingAspect {
@Before("execution(* com.example.service.*.*(..))")
public void log(JoinPoint jp) {
System.out.println("Entering " + jp.getSignature());
}
}
@EnableAspectJAutoProxy.Q2. How do you measure method execution time using AOP?
Use Around advice to capture start and end time.
Example:
Example:
@Around("@annotation(com.example.Timed)")
public Object measureTime(ProceedingJoinPoint pjp) throws Throwable {
long start = System.currentTimeMillis();
Object result = pjp.proceed();
long elapsed = System.currentTimeMillis() - start;
System.out.println(pjp.getSignature() + " took " + elapsed + " ms");
return result;
}
Q3. How would you implement a simple security check using AOP?
Define a custom annotation
Example:
@Secured, and use Before advice to check user role.Example:
@Before("@annotation(secured)")
public void checkSecurity(Secured secured) {
if(!userHasRole(secured.role())) throw new SecurityException();
}
Q4. What is needed to enable AOP in a Spring Boot project?
• Add
• Spring Boot auto-configures AspectJ auto-proxy.
• You can also add
• Then define
spring-boot-starter-aop dependency.• Spring Boot auto-configures AspectJ auto-proxy.
• You can also add
@EnableAspectJAutoProxy manually if needed.• Then define
@Aspect classes as components.Q5. How do you handle exceptions in AOP?
Use
For around advice, you can catch exceptions in the try-catch block around
@AfterThrowing advice to catch exceptions. You can log them or perform custom handling.For around advice, you can catch exceptions in the try-catch block around
proceed().