How to make Tomcat quick in loading changes to make Java web development fast

Question

My app uses Struts2 MVC, Spring JDBC Template with Eclipse IDE and Tomcat. Whenever I change a class code, I have to restart the Tomcat, which waste about 15-20 seconds every time.

I have configured hot-deployment i.e. on-java-class-change, context reloaded automatically, but it often fails, and I have to restart the Tomcat.

What I wish is:

1. When I make a change to JSP, it should be auto loaded, instead of on-1st-request.

2. When a java class is changed and build, only that class should be loaded, without restarting Tomcat, even whole context should not restart or reload.

If someone have used Jetty, please share - does Jetty provide better solution to these issues.

In PHP, you make a change in script, and access that page, its ready. I just wish it in Java.

Answer 1

We are using embedded Jetty at work and it's a blast. See http://wiki.eclipse.org/Jetty/Tutorial/Embedding_Jetty for a guide on embedding Jetty.

The startup time on the Jetty side is extremely fast (1-2 seconds). In our case though spring takes a lot of time to initialize still.

It is easy to configure Jetty to reload jsps automatically just point it to a directory and not war file and jsps will reload automatically, something like this:

public class OneWebAppUnassembled
{
    public static void main(String[] args) throws Exception
    {
        Server server = new Server(8080);

        WebAppContext context = new WebAppContext();
        context.setDescriptor(webapp+"/WEB-INF/web.xml");
        context.setResourceBase("../test-jetty-webapp/src/main/webapp");
        context.setContextPath("/");
        context.setParentLoaderPriority(true);

        server.setHandler(context);

        server.start();
        server.join();
    }
}

Class reloading is possible using hot swap, I don't know if there are ready solutions for when hot swap doesn't work.

Answer 2

Have a look at JRebel. You have to pay for it, but it may be worth it in the long run for the time saved! :)