Graceful Shutdown of Spring Boot Applications: Avoiding kill -9 and Using kill -15, Actuator, and Custom Shutdown Configurations

In Linux, using kill -9 pid forcefully terminates a process, which can cause data inconsistency especially with MyISAM tables or distributed transactions.

For Spring Boot applications, a graceful shutdown is preferred. Sending kill -15 pid triggers an interrupt, allowing the application to finish ongoing requests before stopping.

Graceful shutdown with Spring Boot

Define a controller with a long‑running endpoint and test termination using kill -15. The logs show the interrupt exception and shutdown hook execution.

Using Actuator

Add spring-boot-starter-actuator and enable the /shutdown endpoint in application.yml. A POST request to /shutdown stops the service gracefully.

Custom shutdown configuration

Implement ElegantShutdownConfig that implements TomcatConnectorCustomizer and ApplicationListener<ContextClosedEvent> to pause the connector and wait for thread‑pool termination.

package com.ymy.config;

import org.apache.catalina.connector.Connector;
import org.springframework.boot.web.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class ElegantShutdownConfig implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {
    private volatile Connector connector;
    private final int waitTime = 10;
    @Override
    public void customize(Connector connector) { this.connector = connector; }
    @Override
    public void onApplicationEvent(ContextClosedEvent event) {
        connector.pause();
        Executor executor = connector.getProtocolHandler().getExecutor();
        if (executor instanceof ThreadPoolExecutor) {
            ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
            threadPoolExecutor.shutdown();
            if (!threadPoolExecutor.awaitTermination(waitTime, TimeUnit.SECONDS)) {
                System.out.println("请尝试暴力关闭");
            }
        }
    }
}

Register this bean in the main application class and configure the servlet container to use it.

package com.ymy;

import com.ymy.config.ElegantShutdownConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory;
import org.springframework.boot.web.servlet.server.ServletWebServerFactory;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class ShutdownServerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ShutdownServerApplication.class, args);
    }
    @Bean
    public ElegantShutdownConfig elegantShutdownConfig() { return new ElegantShutdownConfig(); }
    @Bean
    public ServletWebServerFactory servletContainer() {
        TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
        tomcat.addConnectorCustomizers(elegantShutdownConfig());
        return tomcat;
    }
}

Data backup on shutdown

Use a @PreDestroy method in a @Configuration class to perform backup tasks before the JVM stops.

package com.ymy.config;

import org.springframework.context.annotation.Configuration;
import javax.annotation.PreDestroy;

@Configuration
public class DataBackupConfig {
    @PreDestroy
    public void backData() {
        System.out.println("正在备份数据。。。。。。。。。。。");
    }
}

These approaches allow Spring Boot services to stop without data loss, giving time for ongoing requests to finish and for custom cleanup logic to run.