I'm developing an application using the Vaadin framework in Eclipse. I'm using the Tomcat v6.0 servlet and run the application in the Eclipse Web Browser. A problem I've been having though is to have recent changes show in the browser when I test the application.
No matter how many times I restart Tomcat, clean all published resources and restart the Eclipse Web Browser the changes still won't take effect. The changes seem to take effect randomly where time is the biggest factor, which is of great frustration when developing...
So my question is if anyone else has noticed this problem and have any ideas of how to solve it, if there is a configuration I can do or if I'm missing a step in the restart which blocks the changes from taking effect..?
Any help would be greatly appreciated!
In Vaadin most of the code runs in the server and is contained in normal Java files. There are three levels of resource/class changes:
The runtime "hot code replacement". If running Tomcat in debug mode some Java class changes can be published without redeploying the web application. However, if the Tomcat is configured to "auto publish" (check your server settings in Eclipse), the redeployment is automatically done whenever classes change and this causes full context reload and sessions serialization (see #2) . Hot code replacement can be enhanced using tools like JRebel.
Web application deployment. This is essentially deploying a new war file to the server. Causes the previous version to be undeployed and deploys the new version of all classes and resources. Sometimes there are some resources left in the servers work directory or classes are not reloaded, in which case the server restart (#3) is needed.
Server restart. This makes the whole JVM to reload and all the classes and web applications are also reloaded. Still cleaning the work directory separately is needed to make sure everything is reloaded.
In addition to this there is the client-side part of Vaadin (essentially a JavaScript compiled with GWT), which is treated as a static resource by Tomcat. If you modify the client-side Java code the GWT is used to recompile the JavaScript. Deployment should be simply file copying. The browsers cache the generated HTML/JS files, but GWT includes mechanism to avoid this.
You should first try to change the server settings for automatic publishing and see if that helps. Also, I've noticed that different Tomcat version behave differently. This is unfortunate, but the only thing you can do is to try to find the versions/set-up that works for you.
Just to make sure: you have been adding ?restartApplication in the URL to force application to restart on page reload, haven't you?
Related
I am trying to develop my first web-application based on java-EE. This application should be deployed on WildFly application server. For That purpose, I made my inspiration from https://bitbucket.org/lassitercg/example/src.
I made some modifications on my Code.
I am developing this application using IntelliJ-Community. The Application was successfully deployed.
whenever I try to access the application using the following URL localhost:8080/startweb, I get the http status code 404. The code can be found unter this link https://github.com/amitakCsNew/startweb
Since I using Intellij Community edition, I am forced to deploy the application then set the breakpoint in the Controller of the application. The application seems to be succesfully deployed, but I am not jumping to the first breakpoint.
any Idea how I can solve this problem ?
Your webapp layout is wrong. Please refer to the standard Maven directories layout.
You need to move webapp directory to src/main. Then update pom.xml file reference to web.xml, then move META-INF from resources into webapp then fix your syntax errors in index.xhtml (the same h namespace is associated with 2 different URLs), then fix/implement your database, then add faces servlet in web.xml, add faces-config.xml, then your web app should be available at http://localhost:8080/startweb/.
Once you resolve all the problems and the controller code finally executes, you will be able to debug it from the IDE using Remote debug configuration.
If you are new to all of this, I'd suggest starting with something more simple, like a single JSP page and a single Java servlet.
Post the new questions if you have issues describing what you did to solve the problem and what exactly didn't work. The current question is too broad and your sample project has too many issues to cover in the single answer.
I have a GWT project that contains both the GWT UI and the server backend. The server backend contains the Java GWT Services that are exposed via GWT's RPC to the UI.
Since the project has grown quite a bit, with the backend requiring more and more time to start, I am considering moving the UI to a separate project, with the idea to run the backend in a separate VM. The backend is relatively stable, and it is the UI where we spent most time. With the two in separate VMs, we could work on the UI much more efficiently, since we would only reload the UI (in GWT development mode) and leave the backend running.
My question: Is it possible to configure the Google Eclipse Plugin in such a way that it runs the UI and backend in separate VMs and I can still use the GWT development mode?
The project uses GWT 2.4 and we will update to 2.5 as soon as it is out. We use Maven as the build system.
There are two things to consider:
You don't always have to reload the server - usually it's enough to just reload the browser page [*] For an overview of when to reload/restart, ... please see https://stackoverflow.com/a/6150736/291741
You can deploy to an external server. In an Eclipse Run Configuration, go to the Server tab, and uncheck "Run built-in server". This will disable the web server (default port 8888), but will still run the Code Server (default port 9997, see the GWT tab). Then just run your external server (e.g. Tomcat) on port 8888. It should serve the web content, and handle the servlet requests.
If you want to create a really cool fully automated Eclipse-JavaEE + GWT setup, with separate server-side redeploy on any server you like (even with two debugger instances, if you want), see https://stackoverflow.com/a/11700678/291741
[*] I know, there are certain situations, e.g. when changing Gin configuration or Validation annotations, where reloading the web page is unfortunately not enough. But in most cases it just works fine (as long as you run DevMode with "Run As...", not with "Debug As...") If you want to run with a debugger attached, then I'd recommend the external server solution, of course.
Previously i worked with Spring 2.5.6, and whenever i do some changes in jsp pages, i simply refresh the project in eclipse and the change will be reflect.
But then, we are migrating this to 3.0 and everything is fine, but even when i make some changes in JSP, and refresh the project, it is not reflecting. Every time we need to restart the server, to see the changes.
I tried everywhere and didn't get a solution for this.
I am using Eclipse 3.3 + jdk 1.6.0_22 + Windows 7. I am suffering a lot because of this and it would be great if someone helps me fix this issue
Sometimes this can be due to your browser caching, especially "big" files like javascript or css. Couple things to try might be clearing your cache manually, or getting a browser like Firefox or Chrome, using the private browsing feature (nothing is cached in private browsing) and using that to test new features. (This is especially true if you're using the new <resources> bean in Spring MVC, which I believe automatically caches resources it's pointed at)
If this does not work, your container could be set to not republish on application changes.
We have a GWT application which draws some resources from a separate servlet via async javascript. In production this poses no problems as both the producer servlet and the consumer GWT app will reside on the same server, however for development I can't find a way to make this happen as we are head to head with the Same Origin Policy.
As a temporary solution I have the servlet running on Tomcat, and I compile and deploy the GWT app to that same Tomcat instance - this of course works, and it does allow me to attach Eclipse for debugging. However there is the slight problem of the 40 second or so build time for each modification.
We would like to be able to debug via GWT's hosted mode w/ OOPHM - can anybody see a way for us to do this?
Thanks all!
you could use the -noserver option of gwt dev mode, which lets you run your server code with any servlet container.
Maybe you can deploy the producer servlet to Jetty.
http://www.enavigo.com/2008/08/29/deploying-a-web-application-to-jetty/
I think the Jetty home most reside somewhere in the Eclipse directories. A simple file search might help.
Good luck!
If you need just a servlet, why not define it in web.xml and start dev mode as usual?
I use the Hot Swap java debugging feature with web app on Tomcat. After some class signature change, I got "Hot Code Replace Fail" Eclipse dialog - I understand that.
What I want in such case is to republish the application (I can do that) and work with the newly deployed code. However the debugger stil complains, until I restart the server. Because other apps and long startup I don't want that.
Is there a way how to tell to the debugger, that there is the new class version already reloaded in a new webapp classloader and that it is save to continue?
Thanks.
Why don't you try with JRebel?
JRebel is a JVM Java Agent that integrates with application servers, making classes reloadable with existing class loaders. Only changed classes are recompiled and instantly reloaded in the running application.
JRebel plugs into IDEs and build systems. Classes and static resources are loaded straight from the workspace.
http://zeroturnaround.com/software/jrebel/
Regards,
Andrea
There is a old PHD project. The guy who made it was brought by Oracle but his work didnt made it to the Java 8 and hopefully will be seen in Java 9 but is more likely to be in Java 10. There is a new Version of this for Java 8 I guess. I havent tried it yet.
My Original Question for additional information: Advanced Code Hot Swapping in JDK 8?
And the Project page on Github: https://github.com/dcevm/dcevm
With this you can hot replace almost any class change freeing you from restarting the JDK ever after. (beside sideeffects for static objets and singletons but that would be logical)
Did you try Server Options - Serve modules without publishing along with Publishing?
Also not sure what you are saying about other apps.