如何在Jetty源代码中进行调试？

Question

I am assigned a project in which we attempt to push content from a Jetty server to one or more connected clients, using the SPDY protocol. Changes to the current pushing strategy and handlers are required, so I want to change the server's implementation and be able to debug the newly inserted code. I downloaded Jetty's source code from GitHub, and can use the mvn clean install command to generate a distribution in jetty-distribution/target/distribution.

To write my own server handlers en strategies, I loaded all Maven projects in NetBeans, and everything can be build from the top project down. I defined my own handlers, and by passing the right arguments in the project Jetty-Start (jetty home and base) and using the right XML configurations, I can start the server in debug mode from within Java. I can the debug the main class, but in the main, Jetty is executed in another JVM:

// execute Jetty in another JVM
if (args.isExec())
{
    CommandLineBuilder cmd = args.getMainArgs(baseHome,true);
    cmd.debug();
    ProcessBuilder pbuilder = new ProcessBuilder(cmd.getArgs());
    StartLog.endStartLog();
    final Process process = pbuilder.start();
    Runtime.getRuntime().addShutdownHook(new Thread()
    {
        @Override
        public void run()
        {
            StartLog.debug("Destroying " + process);
            process.destroy();
        }
    });

    copyInThread(process.getErrorStream(),System.err);
    copyInThread(process.getInputStream(),System.out);
    copyInThread(System.in,process.getOutputStream());
    process.waitFor();
    System.exit(0); // exit JVM when child process ends.
    return;
}

When accessing the server through the browser, no breakpoint in the server's code is ever triggered. I really need to be able to understand the flow from the request handlers to the pushing strategy, so how can I fully debug the server's implementation?

Answer 1

You can add some parameters into your JVM :Run jetty with this

-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=4000

than run remote and debug with this

-Xnoagent -Djava.compiler=NONE -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=4000

Hope it will helps