Not able to understand spring retry - spring-boot

Question

I'm struggling with understanding #Retryable. What I need is to retry 3 times when I get 5xx Exception and if retry also fails then throw a custom exception in the recovery method. And if some other exception is thrown then catch it and throw a custom exception.
#Retryable(value = HttpServerErrorException.class, maxAttempts = 3, backoff = #Backoff(delay = 3000))
public String callToService(String key) {
String response;
try {
response = //assume a service call here
}catch (Exception ex) {
throw new customException("some message");
}
return response;
}
#Recover
public void retryFailed(HttpServerErrorException httpServerErrorException) {
throw new customException("some message");
}

Answer 1

In your case as you have added:
#Retryable(value = HttpServerErrorException.class, maxAttempts = 3, backoff = #Backoff(delay = 3000))
The #Retryable is used with:
value = HttpServerErrorException.class, so your method will be retried only if HttpServerErrorException is occure/thrown from your method code, and Note: if any other exception thrown retry will not be done, and recover method will also not be invoked, as recover method is only invoked with exception mentioned in value in #Retryable.
maxAttempts = 3, so it will retry executing your method 3 times by maximum
backoff = #Backoff(delay = 3000), so it will keep a delay of 3000ms in between retry.
And after retrying 3 times, if your method still not working, your method with #Recover will be envoked with the HttpServerErrorException
I hope it make sense and help yo understand the concept of #Retryable
Now to implement what you want you need to implement it as below:
#Retryable(value = HttpServerErrorException.class, maxAttempts = 3, backoff = #Backoff(delay = 3000))
public String callToService(String key) {
String response;
try {
response = //assume a service call here
} catch (HttpServerErrorException httpServerErrorException) {
throw httpServerErrorException;
} catch (Exception ex) {
throw new CustomException("some message");
}
return response;
}
#Recover
public void retryFailed(HttpServerErrorException httpServerErrorException) {
//do whatever you want here, when HttpServerErrorException occured more than 3 times
}