Embedded jetty application built by gradle always

Question

I'm experiencing an issue that I do not quite get.

I've written the simplest jetty application:HelloWorldJetty that binds to port 8080 and always returns 'Hello World' on http requests.

The build is configured using gradle. When I use the gradle support netbeans plugin to debug the application, it works and I get the hello world response.

Now when I build the jar and execute it using java -jar HelloWorldJetty.jar, it does bind to port 8080 but all responses have status 500 - internal server error.

I've never worked with an embedded server before and it feels like I'm missing something. Been searching around for days.

Here's the main class:

package com.helloworldjetty;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.AbstractHandler;

/**
 *
 * @author george
 */
public class HelloWorldJetty {
    /**
     * @param args the command line arguments
     */

    public static void main(String[] args) {
        try {
            Server server = new Server(8080);
            server.setHandler(new AbstractHandler() {

                @Override
                public void handle(String string, Request rqst, HttpServletRequest hsr, HttpServletResponse hsr1) throws IOException, ServletException {
                    hsr1.setContentType("text/html;charset=utf-8");
                    hsr1.setStatus(HttpServletResponse.SC_OK);
                    rqst.setHandled(true);
                    hsr1.getWriter().println("<h1>Hello World</h1>");
                }
            });

            server.start();
            server.join();
        } catch (Exception e) {
            e.printStackTrace(System.out);
        }
    }
}

And here's my gradle build script:

apply plugin: 'java'

sourceCompatibility = '1.7'
[compileJava, compileTestJava]*.options*.encoding = 'UTF-8'

// NetBeans will automatically add "run" and "debug" tasks relying on the
// "mainClass" property. You may however define the property prior executing
// tasks by passing a "-PmainClass=<QUALIFIED_CLASS_NAME>" argument.
//
// Note however, that you may define your own "run" and "debug" task if you
// prefer. In this case NetBeans will not add these tasks but you may rely on
// your own implementation.
if (!hasProperty('mainClass')) {
    ext.mainClass = 'com.helloworldjetty.HelloWorldJetty'
}

repositories {
    mavenCentral()
    // You may define additional repositories, or even remove "mavenCentral()".
    // Read more about repositories here:
    //   http://www.gradle.org/docs/current/userguide/dependency_management.html#sec:repositories
}

dependencies {
    // TODO: Add dependencies here ...
    // You can read more about how to add dependency here:
    //   http://www.gradle.org/docs/current/userguide/dependency_management.html#sec:how_to_declare_your_dependencies
    compile group: 'javax', name: 'javaee-api', version: '7.0'
    compile group: 'commons-beanutils', name: 'commons-beanutils', version: '1.8.3'
    compile group: 'commons-httpclient', name: 'commons-httpclient', version: '3.1'
    compile group: 'commons-collections', name: 'commons-collections', version: '3.2.1'
    compile group: 'org.apache.velocity', name: 'velocity', version: '1.7'
    compile group: 'commons-codec', name: 'commons-codec', version: '1.9'
    compile group: 'commons-io', name: 'commons-io', version: '2.4'
    compile group: 'com.google.guava', name: 'guava', version: 'r07'
    compile group: 'commons-lang', name: 'commons-lang', version: '2.5'
    compile group: 'org.apache.httpcomponents', name: 'httpclient', version: '4.3.3'
    compile group: 'org.apache.httpcomponents', name: 'httpmime', version: '4.3.3'
    compile group: 'javax.mail', name: 'javax.mail-api', version: '1.5.4'
    compile group: 'com.googlecode.libphonenumber', name: 'libphonenumber', version: '6.2.2'
    compile group: 'org.slf4j', name: 'jcl-over-slf4j', version: '1.6.1'
    compile group: 'org.slf4j', name: 'slf4j-api', version: '1.6.1'
    compile group: 'org.slf4j', name: 'slf4j-jdk14', version: '1.6.1'
    compile group: 'commons-fileupload', name: 'commons-fileupload', version: '1.2.2'
    compile group: 'commons-validator', name: 'commons-validator', version: '1.4.0'
    compile group: 'org.apache.httpcomponents', name: 'httpcore', version: '4.3.2'
    compile group: 'org.apache.httpcomponents', name: 'httpcore-nio', version: '4.1'
    compile group: 'org.eclipse.jetty.aggregate', name: 'jetty-all', version: '9.3.4.RC0'
    compile group: 'mysql', name: 'mysql-connector-java', version: '5.1.20'
    compile group: 'com.google.code.svenson', name: 'svenson', version: '1.3.8'

    testCompile group: 'junit', name: 'junit', version: '4.10'
}

jar {
    from(configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }) {
        exclude "META-INF/*.SF"
        exclude "META-INF/*.DSA"
        exclude "META-INF/*.RSA"
    }

    manifest {
        attributes 'Implementation-Title': 'HelloWorldJetty',
                'Implementation-Version': 1.0,
                'Built-By': System.getProperty('user.name'),
                'Built-Date': new Date(),
                'Built-JDK': System.getProperty('java.version'),
                'Main-Class': 'com.helloworldjetty.HelloWorldJetty'
    }
}

If anyone could shed some light on this issue I'd really appreciate it.

Answer 1

Having a self-executing uber-jar for a Jetty server is possible.

The Jetty Project even maintains a embedded-jetty-uber-jar example project demonstrating this.

They also maintain a embedded-jetty-live-war example that makes a war file that is also self-executing.

However, these examples both use maven with the uber-jar maven plugin.

Note: the Jetty project has 2 Apache Maven committers on staff

Now to your gradle build.

• Don't use the jetty-all artifact in your build (that's not what that artifact exists for)

  Use specific artifacts for the features / modules that you need.

• Use a stable/released version of Jetty

  9.3.0.RC0 is NOT stable, that's an unstable release candidate.

  As of Oct 27, 2015, the current stable Jetty version is 9.3.5.v20151012

• Merge your webapp metadata (if you have any) into your uber-jar

• Merge your META-INF/services into your uber-jar