JAVA-1098: Add code for the Spring Boot Exit Codes

spring-boot-modules/spring-boot-basic-customization/README.md

@@ -11,3 +11,4 @@ This module contains articles about Spring Boot customization
  - [Spring Boot: Configuring a Main Class](https://www.baeldung.com/spring-boot-main-class)
  - [How to Define a Spring Boot Filter?](https://www.baeldung.com/spring-boot-add-filter)
  - [Guide to the Favicon in Spring Boot](https://www.baeldung.com/spring-boot-favicon)
+ - [Spring Boot Exit Codes](https://www.baeldung.com/spring-boot-exit-codes)

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/exitcode/event/ExitCodeEventDemoApplication.java

@@ -0,0 +1,31 @@
+package com.baeldung.exitcode.event;
+
+import org.springframework.boot.ExitCodeEvent;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.event.EventListener;
+
+@SpringBootApplication
+public class ExitCodeEventDemoApplication {
+
+    public static void main(String[] args) {
+        System.exit(
+            SpringApplication.exit(
+                SpringApplication.run(ExitCodeEventDemoApplication.class, args)
+            )
+        );
+    }
+
+    @Bean
+    DemoListener demoListenerBean() {
+        return new DemoListener();
+    }
+
+    private static class DemoListener {
+        @EventListener
+        public void exitEvent(ExitCodeEvent event) {
+            System.out.println("Exit code: " + event.getExitCode());
+        }
+    }
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/exitcode/exception/ExitCodeExceptionMapperDemoApplication.java

@@ -0,0 +1,31 @@
+package com.baeldung.exitcode.exception;
+
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.ExitCodeExceptionMapper;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+
+@SpringBootApplication
+public class ExitCodeExceptionMapperDemoApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ExitCodeExceptionMapperDemoApplication.class, args);
+    }
+
+    @Bean
+    CommandLineRunner createException() {
+        return args -> Integer.parseInt("test");
+    }
+
+    @Bean
+    ExitCodeExceptionMapper exitCodeToExceptionMapper() {
+        return exception -> {
+            // set exit code based on the exception type
+            if (exception.getCause() instanceof NumberFormatException) {
+                return 80;
+            }
+            return 1;
+        };
+    }
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/exitcode/generator/ExitCodeGeneratorDemoApplication.java

@@ -0,0 +1,22 @@
+package com.baeldung.exitcode.generator;
+
+import org.springframework.boot.ExitCodeGenerator;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ExitCodeGeneratorDemoApplication implements ExitCodeGenerator {
+
+    public static void main(String[] args) {
+        System.exit(
+            SpringApplication.exit(
+                SpringApplication.run(ExitCodeGeneratorDemoApplication.class, args)
+            )
+        );
+    }
+
+    @Override
+    public int getExitCode() {
+        return 42;
+    }
+}

spring-boot-modules/spring-boot/README.MD

@@ -22,7 +22,6 @@ The "REST With Spring" Classes: http://bit.ly/restwithspring
 - [An Introduction to Kong](https://www.baeldung.com/kong)
 - [Spring Boot: Configuring a Main Class](https://www.baeldung.com/spring-boot-main-class)
 - [A Quick Intro to the SpringBootServletInitializer](https://www.baeldung.com/spring-boot-servlet-initializer)
-- [Guide to the Favicon in Spring Boot](https://www.baeldung.com/spring-boot-favicon)
 - [Spring Shutdown Callbacks](https://www.baeldung.com/spring-shutdown-callbacks)
 - [Container Configuration in Spring Boot 2](https://www.baeldung.com/embeddedservletcontainercustomizer-configurableembeddedservletcontainer-spring-boot)
 - [Validation in Spring Boot](https://www.baeldung.com/spring-boot-bean-validation)