Application Exit

Each SpringApplication registers a shutdown hook with the JVM to ensure that the ApplicationContext closes gracefully on exit. All the standard Spring lifecycle callbacks (such as the DisposableBean interface or the @PreDestroy annotation) can be used.

In addition, beans may implement the org.springframework.boot.ExitCodeGenerator 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 return it as a status code, as shown in the following example:

Java
Kotlin

import org.springframework.boot.ExitCodeGenerator;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class MyApplication {

	@Bean
	public ExitCodeGenerator exitCodeGenerator() {
		return () -> 42;
	}

	public static void main(String[] args) {
		System.exit(SpringApplication.exit(SpringApplication.run(MyApplication.class, args)));
	}

}

import org.springframework.boot.ExitCodeGenerator
import org.springframework.boot.SpringApplication
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.context.annotation.Bean

import kotlin.system.exitProcess

@SpringBootApplication
class MyApplication {

	@Bean
	fun exitCodeGenerator() = ExitCodeGenerator { 42 }

}

fun main(args: Array<String>) {
	exitProcess(SpringApplication.exit(
		runApplication<MyApplication>(*args)))
}

Also, the ExitCodeGenerator interface may be implemented by exceptions. When such an exception is encountered, Spring Boot returns the exit code provided by the implemented getExitCode() method.

If there is more than one ExitCodeGenerator, the first non-zero exit code that is generated is used. To control the order in which the generators are called, additionally implement the org.springframework.core.Ordered interface or use the org.springframework.core.annotation.Order annotation.