Spring Boot App not available on its path when deployed on standalone Tomcat

Question

I have a Spring Boot webapp developed and tested with the Netbeans internal Tomcat server.

I have setup the Application as a SpringBootServletInitializer

public class ServletInitializer extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Testspringboot2Application.class);
    }

}


@SpringBootApplication
@RestController
public class Testspringboot2Application {

    @GetMapping("/")
    public String greeting() {
        return "Hello from root path";
    }

    public static void main(String[] args) {
        SpringApplication.run(Testspringboot2Application.class, args);
    }

}

with this pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.2.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>org.theiner</groupId>
    <artifactId>testspringboot2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <name>testspringboot2</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>21</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

I have built the war file (testspringboot2.war) with Netbeans and deployed it on the standalone Tomcat. It was successfully exploded.

But: I cannot reach it on http://tomcatserver:8088/testspringboot2. Do I need to take care of anything else to make this work?

This is true for both Debian 12 and Windows 10 ... so I think this is related to the Spring Boot project rather than the environment

EDIT: Versions

JDK 21
Tomcat 9.0.85 (Debian or Windows)
Apache Netbeans 20
Spring Boot Starter Parent 3.2.2 (start.spring.io with WAR and Maven options selected)

Answer 1

Tomcat 9 is for Jakarta EE8 (javax) which is not compatible with SpringBoot3 release.

I'd suggest going to Tomcat 10 or higher.