When a class file change, Can I make the glassfish server not restart but still reflect the change ?
I mean the glassfish sever doesn't redeployment(or publish) the application, but only redeployment the class that has changed.
There are a number of ways to redeploy an application onto GlassFish 3.1 that do not require that you restart the server.
The method I would recommend is 'asadmin redeploy --name foo --keepstate=true foo.war' (or use directory deployment for the web app...)
You can look at the man page for the redeploy subcommand of asadmin to learn more about the details.
I hardly ever create a deployable archive file.... I usually do directory deployment, which eliminates the time that would get used up creating and then exploding the archive file.
By using directory deployment I can also apply tweaks to jsp files and other static content to test them without a rebuild/redeploy step.
I like to use the keepstate option while I am doing development.
Another important step that you should take to avoid unnecessary restarts is to move to an open-source OS like Linux or Solaris (away from Windows) which has few file locking problems.
If this is meant to be done while development, you can give a shot to JRebel.
Related
I am running my application in production mode (war is not exploded) on a Glassfish server and I want to know if it's possible to hot swap my front end files?
Currently when I do a hot swap, it only does it in the backend (it being Java). Is it possible to also do it for files under the webapp directory?
The Run/Debug Configuration window for Glassfish-within-IntelliJ supports hot deployment:
For exploded artifacts, the available options are:
Update resources. All changed resources are updated (HTML, JSP, JavaScript, CSS and image files).
Update classes and resources. Changed resources are updated; changed Java classes (EJBs, servlets, etc.) are recompiled.
etc
Looks like you need to choose the Update Resources option.
More details in the docs.
Update 1: for packed (i.e. unexploded) artifacts the available options are:
Hot swap classes. Changed classes are recompiled and reloaded at runtime. This option works only in the debug mode.
Redeploy. The application artifact is rebuilt and redeployed.
Restart server. The server is restarted. The application artifact is rebuilt and redeployed.
There is no support for hot deploying 'front end files' in a unexploded artifact.
As I am using eclipse and just set up a dropwizard server. On the command prompt I typed in java -jar target/hello-world-0.0.1-SNAPSHOT.jar server hello-world.yml and is running. Yet when ever I make a change to my eclipse file, like changing the yml file for example it doesn't update. I have to crtl+c and re-run what I typed in above. My question is, is there a faster way of testing so that it updates every time I change something or I just have to deal with the testing. Thanks.
Run from within the IDE
Different Java IDEs permit more efficient workflows. For example, in an IDE you can run up your application using a Runtime Configuration that executes your Service.main() method with parameters of server hello-world.yml. This will save you endless Maven builds.
Unfortunately, with Eclipse the hot swapping of code changes is often cumbersome, so I would recommend that you consider Intellij which is more reliable when it comes to hot swapping code. Even then hot swapping can be risky.
Sometimes a restart is unavoidable
That being said, in your situation hot swapping won't help. You are changing the startup configuration file which is only read at startup. You will have to restart to see the changes unless you create your own dynamic-refresh-on-file-hash-change mechanism (not advised).
One alternative is to put much of your configuration testing in unit tests and verify that your code is responding as expected.
Static assets give an optimal workflow (no restarts)
You may encounter a situation where you only want to change static assets (like JavaScript files) in which case Intellij will allow you to simply recompile on the fly and will copy the changed assets into the /target directory and have them immediately picked up by Dropwizard without a restart.
If you wanted to go one step further you could enlist the services of Grunt.js so that it continuously monitored the src/main/resources/assets (or similar) for changes and then automatically update your /target for you. Again, Intellij will autosave on focus change so this would lead to an optimal workflow where you change the asset, wait one second, refresh browser and see the immediate result.
I wrote a lengthy blog article covering Dropwizard and Ember Data a while ago if you want more details on this approach (and single page web application development in general).
I would like to see how everything is handled behind the scenes behind web servers such as apache httpd and tomcat. How does one go about stepping through these applications, making changes, and then viewing changes?? Applications this complex use scripts for building and I presume they take a while to compile, it seems to me that there would be more to it than simply downloading the source code and importing into Eclipse. Or is it actually that simple?
And how do developers who want to work on the code of these projects get around the fact that it will take a fair amount of time to compile these applications (and other non-trivial applications such as web browsers)? When I am working on smaller stuff I am constantly compiling and then debugging. I imagine that is no feasible when it can take several minutes to compile?
Easy: just read.
http://tomcat.apache.org/tomcat-7.0-doc/building.html
Also, http://wiki.apache.org/tomcat/FAQ/Developing
The current Tomcat 7.0.x trunk takes about 17 seconds to build on my MacBook Pro, and that included downloading a few dependencies that I didn't already have laying around. If you want to re-compile a single .java file, you can re-run the entire build and the toolchain (really just Apache Ant) will figure out which files actually need to be recompiled.
You only modified one source file? Only one source file will be re-compiled when you run ant deploy (you don't even need the "deploy": it's the default). If you use Eclipse or some other similar IDE, it will recompile on the fly and you don't need to worry about the command line or any of that.
If you have further questions, please join the Tomcat users' mailing list (or the developers' list) and join the community.
I've deployed the jboss-as-helloworld-errai application in my standalone jboss7.1 instance, and I deleted it later ( in the */standalone/deployments folder). But every time I restart my server it redeploys that application.
Is there another place where jboss reads the application to deploy?
Best regard
Did you delete the file while the server was running?
Probably, JBoss still finds a deployment information in one your /standalone/configuration/standalone*.xml files (at the end of the file). JBoss unpacks its deployments in one of the /standalone/tmp/vfs/temp* folders. As long as it finds a deployment in your configuration file, it will start the application.
The deployment binaries are located under the standalone/data/content. These would also need to be deleted. The best solution is to properly undeploy the application via CLI, the maven plug-in or the web console.
This does not sound like expected behaviour. Can you please confirm the steps that you are taking when using the deployment folder? For example:
Deploy
Copy application file to /standalone/deployments folder
Deployment Scanner creates a .dodeploy marker file
Deployment Scanner picks up application and creates a .deployed marker file
Application confirmed as deployed (checking the Management Console to confirm)
Undeploy
Application deleted from /standalone/deployments folder
Delete application (or) delete .deployed marker file
Deployment scanner undeploys the application and creates .undeployed marker file
Confirm application removed in console
Restart server
Confirmed removal is persistent
The README.txt file in the deployments folder shows the simple undeployment workflow in one easy step in the command line.
rm $AS/standalone/deployments/example.war.deployed
Documentation
You can read more about the deployment scanner in the official docs. There's a topic about the scanner marker files, as well as a parent topic about the scanner and deployments in general. If you are finding issues with the scanner, it's a bug. You might like to test the expected behaviour, and also try the Management Console.
Red Hat Docs - Reference for Deployment Scanner Marker Files
Red Hat Docs - About Application Deployment
Potential Issues
Don't confuse the Deployment Scanner subsystem (which watches the Deployments folder for the Standalone server instance) with the Management Console or Management CLI deployments process. You might be better off using one of the Management tools instead of the hot deployment capability to allow for more control over the state and presence of your application.
I am to migrate a Websphere machine (including the applications which run on it) to a new machine. They wanted a clean install of the OS and WebSphere, so I did that. I also took a full file backup of all of the applications they had on the old server. The problem is that to re-install them on the new server, the WebSphere dialog asks me for the JAR/EAR/WAR file, which I don't have.
Is there any reasonably easy way to simply extract the backup of the WebSphere application files I have taken from the old maching, and simply configure the new machine to use them? WAR, etc. is a nice feature to have, but to be forced to use it seems silly.
Edit: The existing WebSphere server is still up and running in production.
Edit: The old server is WAS 3.5, which means it doesn't even have an export function, sadly. Also, the directory where it actually runs the content from has a completely different structure (consisting of like a a %/Web and %/Servlet, where % is the context path of the application). In the "Install" section, it doesn't even mention EAR or WAR, only JAR. I am currently thinking that perhaps the best thing to do might be to just copy the directory over to another WAS 3.5 system and then upgrade that system (and hope it converts the folder structure and updated the config as part of the upgrade).
Edit: The closest thing I have found to a solution so far is this link:
http://www.javazoom.net/services/newsletter/was4.html (though I am not sure if that tool is available or relevant for WAS 7.x).
This has to be a problem other people have run into before, but I can't find a solution anywhere on the WEB.
Thank you!
Here do they have sample Jacl scripts one can use to export/import appserver's configuration. So that is what you can start with. If your new bow uses the same version of WAS (and the same topology if it is not a standalone box) as the old one, it might be a (relatively) safe process.
Migration between different versions of Websphere might be somewhat more tricky, but I'm sure IBM published at least one redbook on that topic.
If you still have the old server running, than just export the apps and you have the war/ear files. However, If you don't know the configuration for the apps, you are screwed. However, I am sure IBM has tools that you can use. Some of the paid tools look even nice and user friendly (at least according to their sales demos). I can't tell you what you need, since I don't know what documentation you have for your apps. But as it looks like there is not much there, otherwise you would just install the application the same way they were installed on your old server and use the binaries (war, ear, jar) that are archived somewhere.