From cf2ebbcb2559ade0ae78b1d63b00b68656a12933 Mon Sep 17 00:00:00 2001
From: Tom Hombergs <tom.hombergs@gmail.com>
Date: Wed, 12 Jul 2017 22:43:18 +0200
Subject: [PATCH] Improve ExitCodeGenerator doc

See gh-9740
---
 .../main/asciidoc/spring-boot-features.adoc   | 24 ++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc b/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
index 3ecca74b92d..cfc5363ca2d 100644
--- a/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
+++ b/spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc
@@ -336,7 +336,29 @@ callbacks (such as the `DisposableBean` interface, or the `@PreDestroy` annotati
 be used.
 
 In addition, beans may implement the `org.springframework.boot.ExitCodeGenerator`
-interface if they wish to return a specific exit code when the application ends.
+interface if they wish to return a specific exit code when `SpringApplication.exit()`
+is called. This exit code can then be passed to `System.exit()` to pass it to the outside.
+
+[source,java,indent=0]
+----
+	@SpringBootApplication
+    public class ExitCodeApplication {
+
+    	public static void main(String[] args) {
+    		System.exit(SpringApplication.exit(SpringApplication.run(ExitCodeApplication.class, args)));
+    	}
+
+    	@Bean
+    	public ExitCodeGenerator exitCodeGenerator(){
+    		return () -> 42;
+    	}
+
+    }
+----
+
+Also, the `ExitCodeGenerator` interface may be implemented by exceptions. When such an exception is
+encountered, Spring Boot will return the exit code provided by the implemented `getExitCode()` method
+to the outside caller.