Response received from service to controller class is null after aspect gets executed on service cla

I have a controller class which further calls service class method. An AOP @Around aspect is applied on the service class method.

package com.hetal.example;

@RestController
public class CustomerController {
    @Autowired
    CustomerService customerService;

    @RequestMapping(value = "/getDetails", method = RequestMethod.GET)
    public String getCustomerDetails() {
        System.out.println("Inside controller class");
        String details = customerService.getDetails(custName);
        System.out.println("Customer details is = " + details); // prints null
    }
}

package com.hetal.example;

@Service
public class CustomerServiceImpl implements CustomerService {
    @Override
    public String getDetails(String custName) {
        //some code
        returns "Customer details";
    }
}

An aspect is written to be executed @Around the method getDetails() of CustomerServiceImpl

package com.hetal.config;

public class JoinPointConfig {
   @Pointcut(value="execution(* com.hetal.example.CustomerService.getDetails(..) && args(custName)")) 
   public void handleCustomerDetails(String custName) {}
}

package com.hetal.config;

@Aspect
@Component
public class CustomerAspect {
   @Around("com.hetal.config.JoinPointConfig.handleCustomerDetails(custName)") 
   public Object aroundCustomerAdvice(ProceedingJoinPoint joinpoint, String custName) {
       System.out.println("Start aspect");
       Object result= null;
       try { 
          result = joinpoint.proceed();
          System.out.println("End aspect");
       }
       catch(Exception e) {}
    return result;
   }
}

Execution goes as below,

1. Controller calls CustomerServiceImpl.getDetails method.

2. CustomerAspect is called, prints "Start aspect". //before advice

3. joinpoint.proceed() calls actual CustomerServiceImpl.getDetails method.

4. CustomerServiceImpl.getDetails returns a string "Customer details" and control comes back to the aspect, prints "End aspect" //after returning advice

5. Control goes back to controller class but the response received is null.

I want the response returned from the service class into the controller class after the completion of the aspect.

Thank you in advance !!