Wildfly server running, but returning 404 error Not found no matter what I do

Question

I followed a REST API | Web service tutorial on the web and got stuck midway. When I run the server it setups successfully, shows that its running at http://localhost:8080/ as well but as soon as I try to access different servlets, the page reloads and returns with 404 Error Not found. I tried downloading earlier versions of wildfly with no avail. The paths I tried were /demorest, /webapi, /myresources and they were used in conjunction as well. What could be the problem?

package com.david.demorest;

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

@Path("myresource")
public class MyResource {

@GET
@Produces(MediaType.TEXT_PLAIN)
public String getIt() {
    return "Got it!";
}
}

<?xml version="1.0" encoding="UTF-8"?>
<!-- This web.xml file is not required when using Servlet 3.0 container,
     see implementation details http://jersey.java.net/nonav/documentation/latest/jax-rs.html -->
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <servlet>
        <servlet-name>Jersey Web Application</servlet-name>
        <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
        <init-param>
            <param-name>jersey.config.server.provider.packages</param-name>
            <param-value>com.david.demorest</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Jersey Web Application</servlet-name>
        <url-pattern>/webapi/*</url-pattern>
    </servlet-mapping>
</web-app>

<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/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.david</groupId>
    <artifactId>demorest</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>demorest</name>

    <build>
        <finalName>demorest</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <inherited>true</inherited>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.glassfish.jersey</groupId>
                <artifactId>jersey-bom</artifactId>
                <version>${jersey.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet-core</artifactId>
            <!-- use the following artifactId if you don't need servlet 2.x compatibility -->
            <!-- artifactId>jersey-container-servlet</artifactId -->
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.inject</groupId>
            <artifactId>jersey-hk2</artifactId>
        </dependency>
       
        <dependency>
            <groupId>org.glassfish.jersey.media</groupId>
            <artifactId>jersey-media-json-binding</artifactId>
        </dependency>
       
    </dependencies>
    <properties>
        <jersey.version>3.0.4</jersey.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
</project>

Answer 1

It's likely that the tutorial is written to deploy to Tomcat. Wildfly has everything you need for JaxRS built in.

To get started you will need three files. First, you need a class that extends javax.ws.rs.core.Application. It can be in any package you'd like:

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

@ApplicationPath("/rest")
public class RestApplicationConfig extends Application {
    // intentionally empty
}

Next, you need your service. The one you show should work though I'd have my Path start with a forward slash like @Path("/myresource"). Lastly, you need a pom.xml that produces a war file. I haven't tested yours but I have one that looks like:

<?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/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <artifactId>jaxrs-simple-sample</artifactId>
    <groupId>com.hotjoe.jaxrs</groupId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

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

    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>8.0.1</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.3.2</version>
            </plugin>
        </plugins>
    </build>
</project>

That I just verified works. Once you have all of this you can produce a war file that can be dropped into $WILDFLY_HOME/standalone/deployments and Wildfly will run it. But you need to watch the URL. As defined in my pom.xml this will create a war file named jaxrs-simple-sample-1.0-SNAPSHOT.war and this file name becomes part of the URL. In this example, the URL to your service would be http://localhost:8080/jaxrs-simple-sample-1.0-SNAPSHOT/rest/myresource. The rest part of that comes from the @ApplicationPath defined. But the other part comes from the name of the war. If you don't like that, you can add one more Wildfly specific file:

<?xml version="1.0" encoding="UTF-8"?>
<jboss-web>
    <context-root>myapp</context-root>
</jboss-web>

This file, in a standard Maven environment, would be named jboss-web.xml and would be placed in src/main/webapp/WEB-INF. This would change the above URL to http://localhost:8080/myapp/rest/myresource.