[FIXED] 404 on Controller Endpoint Spring while running on customer server

Issue

I'm getting 404 consistently for a Gradle spring project while running on tomcat 8.5. I created a simple project from https://start.spring.io and imported it into the spring tool suite.

When I run it as spring boot app, I'm able to hit the endpoint http://localhost:8080/healthCheck but when I add it to server I created (tomcat 8.5), I'm getting a 404 error on the same endpoint.

This is my simple controller:

@RestController
public class HealthCheckController {

    @GetMapping("/healthCheck")
    public String healthCheck() {
        return "API is accessible";
    }
}

This is my build.gradle:

plugins {
    id 'org.springframework.boot' version '2.5.4'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
}

group = 'com.demo'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation 'org.springframework.boot:spring-boot-starter-tomcat:2.5.4'
}

test {
    useJUnitPlatform()
}

And this is my main class:

@SpringBootApplication
public class PracticeApplication extends SpringBootServletInitializer  {

    public static void main(String[] args) {
        SpringApplication.run(PracticeApplication.class, args);
    }
    
    @Override
      protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(PracticeApplication.class);
      }

}

I have changed the server location to use Tomcat Installation and hence am able to hit http://localhost:8080 and it comes up with tomcat homepage.

Here's my directory structure for reference:

I'm new to gradle and spring so apologies if its a stupid thing that I'm doing wrong.

Solution

So turns out Apache Tomcat does not take jar files and to run spring boot app on an external tomcat server (non-embedded ones), WAR file is needed to be created.

I added war to my build.gradle and gave it an alias as well

plugins {
    id 'org.springframework.boot' version '2.5.4'
    id 'io.spring.dependency-management' version '1.0.11.RELEASE'
    id 'java'
    id 'war'
}

war {
    archiveName = 'practice.war'
}

After adding the above, I refreshed the Gradle project and restarted the server and then I hit the below endpoint: http://localhost:8080/practice/healthCheck This is different from how we hit the above endpoint on the embedded server which is: http://localhost:8080/healthCheck

Another way to run this is to go to build/libs/ and copy the war into ROOT directory, then run startup.bat from apache/bin/

Answered By - Billy
Answer Checked By - David Goodson (JavaFixing Volunteer)