Spring boot application fails to restart when deployed on external tomcat - spring-boot

Question

I've added restart functionality to my Spring boot application. It works file in my local setup, but fails when deployed on external tomcat. I've implemented the restart functionality by creating a new application context.
The following is my main class:
public class RestartApplication extends SpringBootServletInitializer {
private static ConfigurableApplicationContext context;
private static ClassLoader mainThreadClassLoader;
public static void main(String[] args) {
mainThreadClassLoader = Thread.currentThread().getContextClassLoader();
context = SpringApplication.run(RestartApplication.class, args);
}
#Override
protected SpringApplicationBuilder configure(final SpringApplicationBuilder application) {
return application.sources(RestartApplication.class);
}
public static void restart() {
if (context == null) {
context = (ConfigurableApplicationContext) ApplicationContextListener.getContext();
}
ApplicationArguments args = context.getBean(ApplicationArguments.class);
Thread thread = new Thread(() -> {
context.close();
context = SpringApplication.run(RestartApplication.class, args.getSourceArgs());
});
thread.setContextClassLoader(mainThreadClassLoader);
thread.setDaemon(false);
thread.start();
}
}
I see the following error in tomcat logs:
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.web.embedded.tomcat.TomcatEmbeddedWebappClassLoader
at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:471)
at java.base/java.net.ClassLoader.loadClass(ClassLoader.java:588)
at java.base/java.net.ClassLoader.loadClass(ClassLoader.java:521)
My pom.xml is:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<properties>
<java.version>11</java.version>
</properties>
<packaging>war</packaging>
<name>restart-application</name>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.14</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<description>Demo project for Spring Boot</description>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.3.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<webResources>
<resource>
<directory>${project.basedir}/src/main/resources/drivers</directory>
<targetPath>WEB-INF/lib</targetPath>
</resource>
</webResources>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<finalName>application_restart</finalName>
</build>
</project>
Please let me know if I need to change anything to get the restart working when deployed on external tomcat.
Thanks!