Retry handling with Spring-Retry using @Retryable

Whenever communication happens between software applications ,
 there is a chance of network failure or timeout .
In such case , the failed application should retry the communication to make it success.


Setup

Dependency for Spring-Retry,

<dependency>
  <groupid>org.springframework.retry</groupid>
  <artifactid>spring-retry</artifactid>
  <version>1.1.2.RELEASE</version>
</dependency>

Spring Retry  uses  AOP, so make sure you use Spring AOP ,

<dependency>
  <groupid>org.springframework</groupid>
  <artifactid>spring-aop</artifactid>
  <version>4.2.5.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.aspectj</groupId>
  <artifactId>aspectjweaver</artifactId>
  <version>1.8.8</version>
</dependency>

If you are using Spring Boot, you can use spring-boot-starter-aop instead,

<dependency>
  <groupid>org.springframework.boot</groupid>
  <artifactid>spring-boot-starter-aop</artifactid>
</dependency>

To enable Spring Retry in your application youd need to annotate main class with @EnableRetry annotation.


@EnableRetry
@SpringBootApplication
public class MainApplicationForSpringRetry {
  public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}

 Retry handling using annotation:

Annotate the appropriate methods with @Retryable annotation

@Service
public class RertyService {

  @Retryable
  public void retryMethod() {
    //method to be retried
  }
} 
Methods annotated with @Retryable can be called like any other methods.
Whenever  retryable method fails with an exception, Spring will automatically retry for three times.
By default Spring uses a 1 second delay between method calls.
Please note that the calling thread blocks during retry handling.

The retry can be customized . For example:

@Service
public class MyService {

  @Retryable(value = {Exception1.class, Exception2.class}, maxAttempts = 5)
  public void retryMethodWithException() {
    // your code
  }

  @Recover
  public void recoverMethodForException1(Exception1 exception) {
    // to recover from Exception1
  }
}
Here Spring apply retry handling only if a Exception of type Exception1 or Exception2 is thrown.
Other exceptions will not cause a retry.
maxAttempts = 5 means Spring will retry the method up to 5 times if it fails.

With @Recover we define a separate recovery method for Exception1.
This allows us to run special recovery code when a retryable method fails with Exception1.