Getting 404 while trying to access endpoints using Jersey 3 and Tomcat 10

Question

Been trying for days to fix this problem. Just trying to recreate a simple "Hello World" REST api with Jersey 3 and Tomcat 10 in maven. After creating the WAR file of the project I can access the index.jsp (created by default when I created the project) but when I try to access the "/helloworld" endpoint I get error 404. Here's my code:

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>web-app</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <failOnMissingWebXml>false</failOnMissingWebXml>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-jdk-http</artifactId>
            <version>3.0.2</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.core</groupId>
            <artifactId>jersey-client</artifactId>
            <version>3.0.2</version>
        </dependency>

        <dependency>
            <groupId>jakarta.servlet</groupId>
            <artifactId>jakarta.servlet-api</artifactId>
            <version>5.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jakarta.servlet.jsp</groupId>
            <artifactId>jakarta.servlet.jsp-api</artifactId>
            <version>3.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jakarta.el</groupId>
            <artifactId>jakarta.el-api</artifactId>
            <version>4.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jakarta.websocket</groupId>
            <artifactId>jakarta.websocket-api</artifactId>
            <version>2.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jakarta.security.enterprise</groupId>
            <artifactId>jakarta.security.enterprise-api</artifactId>
            <version>2.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>jakarta.platform</groupId>
            <artifactId>jakarta.jakartaee-web-api</artifactId>
            <version>9.0.0</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>web-app</finalName>
    </build>
</project>

HelloWorldResource

/*
 * Copyright (c) 2010, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package jersey;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

/**
 *
 * @author Jakub Podlesak
 */
@Path("helloworld")
public class HelloWorldResource {
    public static final String CLICHED_MESSAGE = "Hello World!";

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getHello() {
        return CLICHED_MESSAGE;
    }

}

JaxRsApplication

/*
 * Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
package jersey;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import jakarta.ws.rs.ApplicationPath;
import jakarta.ws.rs.core.Application;

/**
 * JAX-RS Application class for this example.
 *
 * @author Martin Matula
 */
@ApplicationPath("/api")
public class JaxRsApplication extends Application {
    private final Set<Class<?>> classes;

    public JaxRsApplication() {
        HashSet<Class<?>> c = new HashSet<Class<?>>();
        c.add(HelloWorldResource.class);
        classes = Collections.unmodifiableSet(c);
    }

    @Override
    public Set<Class<?>> getClasses() {
        return classes;
    }
}

The error Picture

Using jdk 11, and I've tried deploying both in a Docker with Tomcat 10 and locally directly downloading the Tomcat Server into my PC.

Suggestions?

Answer 1

Jersey requires an appropriate container module to deploy the REST application. You added jersey-container-jdk-http, which works with a JDK Http Server (cf. documentation).

What you need instead is the jersey-container-servlet module (cf. documentation), which works in every Servlet 3.x environment. Therefore you need to add this dependency:

<dependency>
    <groupId>org.glassfish.jersey.containers</groupId>
    <artifactId>jersey-container-servlet</artifactId>
    <version>3.0.2</version>
</dependency>

Remark: Tomcat 10 is not a complete Jakarta EE 9 server, so you should also remove the jakarta.jakartaee-web-api dependency.