Apply Spring Boot's Application Exit support

Closes gh-40

Author: izeye

README.adoc

@@ -224,6 +224,9 @@ include::complete/src/main/java/com/example/batchprocessing/BatchProcessingAppli
 
 include::https://raw.githubusercontent.com/spring-guides/getting-started-macros/master/spring-boot-application-new-path.adoc[]
 
+Note that `SpringApplication.exit()` and `System.exit()` ensure that the JVM exits upon job completion.
+See the https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-application-exit[Application Exit section in Spring Boot Reference documentation] for more details.
+
 For demonstration purposes, there is code to create a `JdbcTemplate`, query the database,
 and print out the names of people the batch job inserts.
 

complete/src/main/java/com/example/batchprocessing/BatchProcessingApplication.java

@@ -7,6 +7,6 @@
 public class BatchProcessingApplication {
 
 public static void main(String[] args) throws Exception {
-SpringApplication.run(BatchProcessingApplication.class, args);
+System.exit(SpringApplication.exit(SpringApplication.run(BatchProcessingApplication.class, args)));
 }
 }