Massively messed up production issue:
I have inherited a massive ( 1 million line code base ) web application that my predecessors botched up completely.
They thought it would be a wonderful idea to just add the WEB-INF/classes directory the the system classpath in the startupWeblogic script instead of properly packaging up the application in an ear or war file, and manually point all the paths in the console to the various non-standard paths they just conceived of themselves.
Now my problem is I have to install another application as a proper war file that uses classes with the same packages and names, just even older code, into the same Weblogic 10.3.6 instances. But as you can imagine the stuff that is hacked into the system classpath takes precedence over everything in the additional webapp, even with the prefer web app lib preference set in the weblogic.xml file.
Notes:
Repackaging the offending application is not an option on my timeline, it is going to be done, but just not in the timeline I have to meet. Running on other instances of Weblogic isn't in my timeline either, I don't have the time to go through the provisioning process to get the assets in time.
Given this how can I get this additional webapp to play nice and deploy in the same weblogic instance as the one that is hacked into the system classpath.
If someone can give me an answer that solves this issue, I will make sure to put a massive bounty on this when I am able to and award it to you after the fact. The sooner the answer the bigger the bounty will be!
Did you try prefer-application-packages within the weblogic-application.xml as well?
The mechanism that Weblogic calls the Filtering Classloader, here are the links:
http://docs.oracle.com/cd/E15051_01/wls/docs103/programming/classloading.html#wp1097187
http://hasamali.blogspot.in/2011/08/weblogic-identifying-class-conflict-and.html
http://atheek.wordpress.com/2011/12/20/weblogic-filtering-classloaders/
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I have a webapp in a war archive which is deployed on cloudfoundry.
One of the libraries ("somelib.jar") used by the app is made by another developer.
I would like a way for him to upload several different versions of somelib.jar and test the behaviour of the app.
I have managed to get the jar uploaded to WEB-INF/lib directory of the deployment. I have also managed to unpack the jar into WEB-INF/classes. However, I have not managed to get the new version of the jar to be used. I tried various hacks such as those described in this question and this question without any luck.
Everytime, the classes/jars that get loaded the first time get used after that, even if we replace the actual .class or .jar file in the above directories.
Is there any easy way to achieve what I want?
Note: Since I dont have control of Tomcat (where it runs), I cannot configure Tomcat or make any changes to the server. I just have control on my war file, so everything needs to be done programmatically.
EDIT: the reason I want this is to reduce our testing time. Currently someone gives me a new version of somelib.jar, I repackage it into my application, upload to CF, send him a notification, then he tests the behavior of the new jar. What I would have preferred is that he upload his jar directly to CF and do the testing whenever he has a new version without the unnecessary intermediate delay.
In tomcat 7, you can version your WAR file and the new versions will gradually kick in.
http://www.tomcatexpert.com/blog/2011/05/31/parallel-deployment-tomcat-7
In order for you to control the application server yourself, you would need to deploy a standalone app into Cloud Foundry.
This blog should help you out with that:
http://blog.cloudfoundry.com/2012/05/11/running-standalone-web-applications-on-cloud-foundry/
This way you can custom configure your tomcat.
Everytime, the classes/jars that get loaded the first time get used after that, even if we replace the actual .class or .jar file in the above directories
That's the way that normal Tomcat (Java EE) classloading works. Your classes are loaded when first deployed, and any changes will be ignored (JSPs are managed slightly differently, but only in a development environment).
You should be able to solve this problem by using the Equinox OSGi bridge servlet. I haven't done this myself, but here's a writeup by a person that I respect.
We have developed a web based application in java(STRUTS 2.0). Now we want to deploy the application. The client is having one pre UAT environment ,UAT environment and a production environment.
Now when we are deploying for pre-UAT we have created the copy of our project and renamed it to pre-UAT. Similarly we are planning for UAT environment and one we already have for development. So in all we will be having 3 copies of our code.
I want to ask is this approach correct or what is the standard approach followed. This is not our final release as we are first releasing a version and then we will be working on other modules.
So please can anyone guide me for approach to follow for creating this 3 different environments.Thanks in advance
I am not sure what you refer to by "we will be having 3 copies of our code". If you are implying that you actually copied the code-base around multiple times, please stop reading and refer to this:
Why is "copy and paste" of code dangerous?
And once you finish reading, do some research about source control and how to use branching/tagging for concurrent development.
If you were referring to multi-environment deployment:
Assuming your application is designed correctly (and I'm treading very carefully here), one WAR file (you were mentioning you're using Tomcat, so I am concluding that your application is packaged as a WAR) should be sufficient. The application code should be environment-independent and should read its environment-specific configuration from external resources, such as a database, configuration files or JNDI.
If your application code is environment-independent, then all you need to do is simply deploy the WAR file to each of the environments (the same WAR file), plus the environment-specific set of external artifacts (such as configuration files).
In my source code, I'd like to get programmatically, the last modified date of the current EAR from which my code is deployed.
I'm using Oracle WebLogic.
How could I do that?
Thx for your answers
I'd suggest stepping back and looking at the problem you're trying to solve, Eric.
Do you want to know when the application was built or the particular version of the application you've got deployed? If that's the case, you're probably best served by incorporating something into the build process to set this. Ideally a manifest of the specific component versions used to package up your application.
If you want to know when the application was first deployed by an administrator, or most recently deployed that gets more tricky. Relying on the filesystem to solve this problem is a bad idea because you're at the mercy of whatever WebLogic Server is doing, which is admittedly more than a bit opaque.
If you absolutely need to do this, WebLogic Server's standard staging behaviour puts a version of the file in a particular subdirectory on each server instance, then very quickly pulls it apart. (it's the 'servers//stage' subdirectory underneath the root directory of the domain ($DOMAIN_HOME) $DOMAIN_HOME is the current directory for all server processes at runtime, so the relative path should work fine.
That should give you the time that file was deployed across the network, but you'd definitely want to test the observed behaviour from rebooting your server instance.
The problem with that is that it doesn't give you anything you couldn't determine more elegantly via either the build process, or WLST scripting around the deployment process.
If it's the last time the application itself was deployed (regardless of the version) then application lifecycle event listeners are definitely the best way to go. Unfortunately there's no MBean that gives you the uptime of an individual application.
There's a great reference on lifecycle listeners here:
http://download.oracle.com/docs/cd/E17904_01/web.1111/e13712/app_events.htm#i178290
You could either check the file properties or see inside the MANIFEST.MF present inside the EAR.
I am just investigating the idea of this so have no example code. I've been digging around on the web but I'm not really sure what I should actually be looking for so I'm not finding much. So I thought I'd ask and see if anyone knew if a) This is possible. b) How I should do it. (Or at least what I should be looking to learn about to do it.)
I'm building a web app using JSP pages on the client with a JBoss server running J2EE, in the middle there is a tomcat web server.
Basically the app contains different sections that will be rolled out over time as they're developed and also customers may be using different combinations of sections. The tidiest way of deploying this I can think of is to build each section into it's own jar. Then depending on the combination of sections that are relevant for the customer, install only the required jars on the JBoss server for deployment.
To support this I'd like the client navigation menu to only show the available sections based on what is deployed on the JBoss server. Is it possible for my servlet to find out what is deployed on the server? I'd like the solution to be as 'dumb' as possible, i.e. I don't want to tell it what to look for, (other than a prefix to identify our jars), as I don't know yet everything we might build.
My current solution is to have a table in the database to hold a list of the installed sections. But this is going to require update scripts etc during install and I'm sure we should be able to do this by just deploying jars on the server.
Thanks in advance.
You could add this information to the MANIFEST.MF file and then enumerate all files in your webapp (see this answer for how to list all manifests) when you start.
I do something similar by configuring a "Plugin Directory" setting for my application. It then scans that directory regularly for Jars. It looks for specific metadata in the manifest to determine whether the Jar is actually a valid plugin, and what class to load from it (the static initializer of that class registers the plugin with the application).
Then all you need to do is place a new Jar into that directory to add its functionality.
At our shop, we are maintaining roughly 20 Java EE web applications. Most of these applications are fairly CRUD-like in their architecture, with a few of them being pretty processor intensive calculation applications.
For the deployment of these applications we have been using Hudson set up to monitor our CVS repository. When we have a check-in, the projects are set to be compiled and deployed to our Tomcat 6.0 server (Solaris 10, sparc Dual-core 1.6 GHz processor, 2 GB RAM...not the beefiest machine by any stretch of the imagination...) and, if any unit-tests exist for the project, those are executed and the project is only deployed if the unit-tests pass. This works great.
Now, over time, I've noticed myself that a lot of the projects I create utilize the same .jar files over and over again (Hibernate, POI (Excel output), SQL Server JDBC driver, JSF, ICEFaces, business logic .jar files, etc.). Our practice has been to just keep a folder on our network drive stocked with all the default .jar files we have been using, and when a new project is started we copy this set of .jar files into the new project and go from there...and I feel so dirty every time this happens it has started to keep me up at night. I have been told by my co-workers that it is "extremely difficult" to set up a .jar repository on the tomcat server, which I don't buy for a second...I attribute it to pure laziness and, probably, no desire to learn the best practice. I could be wrong, however, I am just stating my feelings on the matter. This seems to bloat the size of our .war files that get deployed to the server as well.
From my understanding, Tomcat itself has a set of .jar files that are accessible to all applications deployed to it, so I would think we would be able to consolidate all of these duplicate .jar files in all our projects and move them onto the tomcat server. This would involve only updating one .jar file on the server if, for example, we need to update the ICEFaces .jar files to a new version.
Another part of me says that by including only one copy of the .jar files on the server, I might need to keep a copy of the server's lib directory in my development environment as well (i.e. include those .jar files in eclipse dependency).
My gut instinct tells me that I want to move those duplicated .jar files onto the server...will this work?
I think Maven and Ivy were born to help manage JAR dependencies. Maybe you'll find that those are helpful.
As far as the debate about duplicating the JARs in every project versus putting them in the server/lib, I think it hinges on one point: How likely is it that you'll want to upgrade every single application deployed on Tomcat at the same time? Can you ever envision a time where you might have N apps running on that server, and the (N+1)th app could want or require a newer version of a particular JAR?
If you don't mind keeping all the apps in synch, by all means have them use a common library base.
Personally, I think that disk space is cheap. My preference is to duplicate JARs for each app and put them in the WAR file. I like the partitioning. I'd like to see more of it when OSGi becomes more mainstream.
It works most of the time, but you can get into annoying situations where the jar that you have moved into tomcat is trying to make an instance of a class in one of your web application jars, leading to ClassNotFoundException s being thrown. I used to do this, but stopped because of these problems.
I really don't think putting libraries in common/lib is a good idea. The idea behind the use of war files as applications into a servlet container, is to have a real idea of isolation between your webapps. You could face errors like deploy some third party WAR (with it own libraries inside WEB-INF/lib) and it behave unexpectedly because it loaded other version of one of it libraries from the common one (remember that the regular behavior for load classes is first look at the common classloader and if you don't find the class look into the one for your webapp). Don't even mention how painful could be to move some application to other servlet container or an Application Server.
As mentioned before, you could use maven to deal with jar dependencies, and if you like the homogeneous use of libraries, define a POM parent (maven jargon) across all your applications.
In my experience you should be very careful with sharing libraries between web applications by moving them into the web container itself.
Let them live in WEB-INF/lib so your wars are self contained (you WILL be glad you did one day).
What you might consider is employing maven or Ant Ivy to pull in library jars from a common repository instead. This is very useful and should not be a problem in your scenario.
Edit: A notable exception is the Metro library - web service layer from Glassfish - which needs to be in the web container and not in the web application.