I'm new to Karaf. I have a jar that has a class App with a method main. When I drop the jar in the The Karaf log service console says the bundle is started but nothing seems to happen. The first thing (the jar) does is a simple database write so I can see if it's running (no log file is generated although one is expected).
The jar depends on lots of other jars. Our sysadmin will not install Maven on the production servers. Where does one put helper jars (like mysql-connector-java-[version].jar)?
Does Karaf use the Manifest file to find the main class? Do I have to implement some special interface or something?
thanks for any help.
As Karaf is a OSGi Container, you should first read some stuff on how to write proper OSGi bundles.
First of all you'll need a Activator that'll start your bundle (just like a main). A Main Class is never interpreted. Yes Karaf, as it is a OSGi container, does "read" the Manifest, but to make sure first it's a proper OSGi bundle second how the resolving should take place by reading Package-Import/-Export.
Regarding the "Packaging" - using lot's of other jar's/bunldes - , you'd either can built a custom Karaf (read the Karaf documentation on how to do this) or create a KAR for your Bundles containing your bundles and a feature.xml (again take a look at the documentation at Karaf)
Currently I create a new war file for each change but the changes are taking place in only a few classes and the Spring applicationContext.xml.
I would like to just update a jar file that contains these classes and not continually re-deploy hundreds of files that have not changed. I can create the jar easily enough but where do I put it and do I have to tell Spring to look in a specific jar for its' config files?
It is quite impossible to hot-redeploy code in Tomcat without using extra tools like JRebel or custom JVM agents.
But it is possible to modularize you application by:
1: Putting JARs to $TOMCAT_HOME/lib. Never do this, this solution is good only for simple cases.
2: Tune context.xml, putting Loader in it, like below:
<Context antiJARLocking="true" path="/">
<Loader className="org.apache.catalina.loader.VirtualWebappLoader" virtualClasspath="${catalina.base}/my-app-plugins/*.jar"/>
</Context>
This will enable you putting JAR file in $TOMCAT_HOME/my-app-plugins and thet will be added to the classpath of you app. You should put context.xml to the src/main/webapp/META-INF folder (Maven layout). However, restart is still needed.
3: Use OSGi. May be an overkill.
I have two ejb jars packaged into a ear. say EJb1.jar adn Ejb2.jar. I am deploying it in Webphere 7.0. Ejb1 is referencing to classes in Ejb2.jar. Unless I specify the Ejb2.jar in Manifest.Mf file of Ejb1.jar, the deployment of EAR file fails.
Throws error that build path is incomplete and that referenced class is not found.
Is there any way I can overcome this ? Through some settings in WebSphere console?
I have too many ejb's in this ear referencing each other.
It makes things really difficult to update manifest file each time we make code changes.
Any ideas ?
If you want to avoid that what you need to do is create and EJB Client Jar which holds the interfaces and put it in the EAR/lib directory.
For example if EJB1.jar got MyBean.java and MyBeanLocal.java you will now split it to 2 jars files:
EJB1.jar (EJB Module) holding MyBean.java and EJB1-Client.jar (Utility Jar) holding MyBeanLocal.java
Then you put EJB1-Client.jar in the EAR file lib directory and EJB2.jar will be able to find the interfaces in its classpath.
Hi I'm facing with a bug in old ejb application which is deployed on IBM Websphere 6.1. Previously it ran but now it stopped for some reason which I have to investigate.
I'm trying to get it to run locally on my desktop, and I'm trying to access the session bean with IBM's launchclient application. I pass in the ear as the argument (yes that's IBM specific) and the ears contains both the ejb-jar and the ejb-client.jar (also IBM specific).
Launchclient fails with the message: myear does not contain an Application Client jar file. Which may be true, but it does contain the client-ejb jar file, which I even bothered to address with -CCjar=MyEjbClient.jar.
My question is how can I make an application client jar file?
I cant find much information on the launchclient thing, I do have RAD 7.x or something, but to be honest I want to stay away from it as much as possible and it's getting really frustrating.
regards,
PS someone knows a nice NO IBM job?
It is not sufficient to have an ejb-client-jar, you need an application client JAR. Also, -CCjar can only be specified for an application jar (and it's not necessary if you only have one).
To add an application client JAR to an EAR, you need to:
Create a Java class with a traditional main method.
Package the class in a JAR in the EAR.
Add a Main-Class to the META-INF/MANIFEST.MF in the JAR.
Add a META-INF/application-client.xml file to the JAR.
Add the module to application.xml in the EAR:
<module>
<java>MyClient.jar</java>
</module>
In my web application I have to send email to set of predefined users like finance#xyz.example, so I wish to add that to a .properties file and access it when required. Is this a correct procedure, if so then where should I place this file? I am using Netbeans IDE which is having two separate folders for source and JSP files.
It's your choice. There are basically three ways in a Java web application archive (WAR):
1. Put it in classpath
So that you can load it by ClassLoader#getResourceAsStream() with a classpath-relative path:
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("foo.properties");
// ...
Properties properties = new Properties();
properties.load(input);
Here foo.properties is supposed to be placed in one of the roots which are covered by the default classpath of a webapp, e.g. webapp's /WEB-INF/lib and /WEB-INF/classes, server's /lib, or JDK/JRE's /lib. If the propertiesfile is webapp-specific, best is to place it in /WEB-INF/classes. If you're developing a standard WAR project in an IDE, drop it in src folder (the project's source folder). If you're using a Maven project, drop it in /main/resources folder.
You can alternatively also put it somewhere outside the default classpath and add its path to the classpath of the appserver. In for example Tomcat you can configure it as shared.loader property of Tomcat/conf/catalina.properties.
If you have placed the foo.properties it in a Java package structure like com.example, then you need to load it as below
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
InputStream input = classLoader.getResourceAsStream("com/example/foo.properties");
// ...
Note that this path of a context class loader should not start with a /. Only when you're using a "relative" class loader such as SomeClass.class.getClassLoader(), then you indeed need to start it with a /.
ClassLoader classLoader = getClass().getClassLoader();
InputStream input = classLoader.getResourceAsStream("/com/example/foo.properties");
// ...
However, the visibility of the properties file depends then on the class loader in question. It's only visible to the same class loader as the one which loaded the class. So, if the class is loaded by e.g. server common classloader instead of webapp classloader, and the properties file is inside webapp itself, then it's invisible. The context class loader is your safest bet so you can place the properties file "everywhere" in the classpath and/or you intend to be able to override a server-provided one from the webapp on.
2. Put it in webcontent
So that you can load it by ServletContext#getResourceAsStream() with a webcontent-relative path:
InputStream input = getServletContext().getResourceAsStream("/WEB-INF/foo.properties");
// ...
Note that I have demonstrated to place the file in /WEB-INF folder, otherwise it would have been public accessible by any webbrowser. Also note that the ServletContext is in any HttpServlet class just accessible by the inherited GenericServlet#getServletContext() and in Filter by FilterConfig#getServletContext(). In case you're not in a servlet class, it's usually just injectable via #Inject.
3. Put it in local disk file system
So that you can load it the usual java.io way with an absolute local disk file system path:
InputStream input = new FileInputStream("/absolute/path/to/foo.properties");
// ...
Note the importance of using an absolute path. Relative local disk file system paths are an absolute no-go in a Java EE web application. See also the first "See also" link below.
Which to choose?
Just weigh the advantages/disadvantages in your own opinion of maintainability.
If the properties files are "static" and never needs to change during runtime, then you could keep them in the WAR.
If you prefer being able to edit properties files from outside the web application without the need to rebuild and redeploy the WAR every time, then put it in the classpath outside the project (if necessary add the directory to the classpath).
If you prefer being able to edit properties files programmatically from inside the web application using Properties#store() method, put it outside the web application. As the Properties#store() requires a Writer, you can't go around using a disk file system path. That path can in turn be passed to the web application as a VM argument or system property. As a precaution, never use getRealPath(). All changes in deploy folder will get lost on a redeploy for the simple reason that the changes are not reflected back in original WAR file.
See also:
getResourceAsStream() vs FileInputStream
Adding a directory to tomcat classpath
Accessing properties file in a JSF application programmatically
Word of warning: if you put config files in your WEB-INF/classes folder, and your IDE, say Eclipse, does a clean/rebuild, it will nuke your conf files unless they were in the Java source directory. BalusC's great answer alludes to that in option 1 but I wanted to add emphasis.
I learned the hard way that if you "copy" a web project in Eclipse, it does a clean/rebuild from any source folders. In my case I had added a "linked source dir" from our POJO java library, it would compile to the WEB-INF/classes folder. Doing a clean/rebuild in that project (not the web app project) caused the same problem.
I thought about putting my confs in the POJO src folder, but these confs are all for 3rd party libs (like Quartz or URLRewrite) that are in the WEB-INF/lib folder, so that didn't make sense. I plan to test putting it in the web projects "src" folder when i get around to it, but that folder is currently empty and having conf files in it seems inelegant.
So I vote for putting conf files in WEB-INF/commonConfFolder/filename.properties, next to the classes folder, which is Balus option 2.
Ex: In web.xml file the tag
<context-param>
<param-name>chatpropertyfile</param-name>
<!-- Name of the chat properties file. It contains the name and description of rooms.-->
<param-value>chat.properties</param-value>
</context-param>
And chat.properties you can declare your properties like this
For Ex :
Jsp = Discussion about JSP can be made here.
Java = Talk about java and related technologies like J2EE.
ASP = Discuss about Active Server Pages related technologies like VBScript and JScript etc.
Web_Designing = Any discussion related to HTML, JavaScript, DHTML etc.
StartUp = Startup chat room. Chatter is added to this after he logs in.
It just needs to be in the classpath (aka make sure it ends up under /WEB-INF/classes in the .war as part of the build).
You can you with your source folder so whenever you build, those files are automatically copied to the classes directory.
Instead of using properties file, use XML file.
If the data is too small, you can even use web.xml for accessing the properties.
Please note that any of these approach will require app server restart for changes to be reflected.
Assume your code is looking for the file say app.properties. Copy this file to any dir and add this dir to classpath, by creating a setenv.sh in the bin dir of tomcat.
In your setenv.sh of tomcat( if this file is not existing, create one , tomcat will load this setenv.sh file.
#!/bin/sh
CLASSPATH="$CLASSPATH:/home/user/config_my_prod/"
You should not have your properties files in ./webapps//WEB-INF/classes/app.properties
Tomcat class loader will override the with the one from WEB-INF/classes/
A good read:
https://tomcat.apache.org/tomcat-8.0-doc/class-loader-howto.html