package com.sample.myApp.exceptions;

public class CustomSpringBootException extends RuntimeException {

private static final long serialVersionUID = 1L;

public CustomSpringBootException(String message) {
super(message);
}

}

package com.sample.myApp.runners;

import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

import com.sample.myApp.exceptions.CustomSpringBootException;;

@Component
public class MyCommandLineRunner implements CommandLineRunner {

@Override
public void run(String... args) throws Exception {

  System.out.println("************************");
  System.out.println("Inside \"MyCommandLineRunner\" and going to throw \"CustomSpringBootException\"");
  System.out.println("************************");

throw new CustomSpringBootException("Exception thrown from \"MyCommandLineRunner\"");
}

}

package com.sample.myApp;

import org.springframework.boot.ExitCodeEvent;
import org.springframework.boot.ExitCodeExceptionMapper;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.EventListener;

import com.sample.myApp.exceptions.CustomSpringBootException;

@SpringBootApplication
public class Application {

public static void main(String[] args) {
  ConfigurableApplicationContext applicationContext = SpringApplication.run(Application.class, args);

  System.out.println("Closing Application Context");

int exitCode = SpringApplication.exit(applicationContext);

  System.out.printf("Application Context is exited with : %d", exitCode);

}

@Bean
 ExitCodeExceptionMapper exitCodeExceptionMapper() {
return exception -> {

if (exception.getCause() instanceof CustomSpringBootException) {
    System.out.println("I am in Exception mapper");
return 10;
} else if (exception.getCause() instanceof ArrayIndexOutOfBoundsException) {
return 11;
}
return 1;
};
}

@Bean
public ExitCodeEventModel exitCodeEventModelIntance() {
return new ExitCodeEventModel();
}

private static class ExitCodeEventModel {

public ExitCodeEventModel() {
   System.out.println("Instantiating ExitCodeEventModel object");
}

@EventListener
public void exitCodeEvent(ExitCodeEvent event) {
   System.out.println("*************************************");
   System.out.println("exit code: " + event.getExitCode());
   System.out.println("*************************************");
}
}
} 

************************
Inside "MyCommandLineRunner" and going to throw "CustomSpringBootException"
************************
I am in Exception mapper
*************************************
exit code: 10
*************************************

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-05-14 08:20:52.940 ERROR 10824 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
 at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:781) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:335) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 at com.sample.myApp.Application.main(Application.java:17) [classes/:na]
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
 at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
 at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
 at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.1.RELEASE.jar:2.0.1.RELEASE]
Caused by: com.sample.myApp.exceptions.CustomSpringBootException: Exception thrown from "MyCommandLineRunner"
 at com.sample.myApp.runners.MyCommandLineRunner.run(MyCommandLineRunner.java:18) ~[classes/:na]
 at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:797) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
 ... 10 common frames omitted