Jboss Module Slot

4/3/2022

Jboss Module Slot

Jboss Module Slot 4,5/5 8692 votes

Jboss Global Module Slot
Jboss Module Slot Machines
Jboss-deployment-structure Module Slot
Jboss Module Sloth

The value of 'slot' is used by the running software to identify the 'slot' portion of the identifier of a jboss-modules module. The software uses the slot to load a module named org.jboss.as.product:slot property, e.g. The software will then read manifest properties included in the META-INF/MANIFEST.MF file. For single-server installations, you may use jboss profile located at appserver root standalone configuration as a template. For cluster installations, use jboss profile located at appserver root domain as a template. It is recommended that you make a copy of the profile (all or standard) and make changes to the copied profile. A WildFly module (or JBoss module) is a packaged collection of classes and other resources, along with the specification of what is imported and exported by this module from/to other modules. Each API or service provided by WildFly is implemented as a module, which is loaded or unloaded on demand. Rajendrapopuri October 28th, 2016 on 6:10 pm. Hi Jay, How to load application properties files in JBoss instances at run time? Currently I created a module under modules folder and placed application configuration properties folders in that folder. The command we will use is 'module' and you need to provide three arguments: the module name, the resources (JAR files) and the dependencies used. Optionally you can add a module slot, in case your module uses several different implementations. Here's the script for creating a MySQL module (line 1) + driver (line 2) + data source (line 3).

Hi,
AS 7 does classloading right. It uses JBoss Modules to provide true application isolation, hiding server implementation classes from the application and only loading the classes your application needs. Modules, packaged as collections of classes, are peers that remain isolated unless explicitly defined as a dependency of another module. Visibility rules have sensible defaults, yet can be customized.

Modular classloading is one of the greatest and amazing feature of JBossAS7, but some application server admins are not much aware of this new feature. So here we are going to see a practicle demo of creating a module on JBoss AS7.1.1.Final.

Few Points Which we are going to discuss here:

Point-1). How to create our own custom modules?

Point-2). What is the need of “module.xml” and where to place it?

Point-3). What is “slot” and Why and When to define “slot” in our “module.xml” file?

Point-4). How to reference a module inside our webapplication for classloading purpose?

Point-5). How and why to use the “META-INF/jboss-deployment-structure.xml” or “WEB-INF/jboss-deployment-structure.xml” file?

***NOTE*** This demo is also available in Github:
https://github.com/jaysensharma/MiddlewareMagicDemos/tree/master/JBossAS7_module_slot_Demo

Developing a Custom Module:

Step-1). Create a directory somewhere in your file system where we will develop our own custom Module with some different versions of class files. Suppose the directory is “/home/userone/CustomModuleTest”

Step-2). Now create a directories structure as “aaa/bbb/1.0” and “aa/bbb/main” inside the directory “/home/userone/CustomModuleTest”.

Step-3). Now write a class with name “Test.java” inside “/home/userone/CustomModuleTest/aaa/bbb/1.0” as following:

Step-4). Similarly write a “Test.java” program as following inside the directory “/home/userone/CustomModuleTest/aaa/bbb/main” :

***NOTE***: The class “aaa.bbb.Test” is same as mentioned in Step3 and Step4 but there is a slight different in the implementation of these classes like the Version of the class is 1.0 and 1.2 as you can see in the static block of the code. This is just to demonstrate that how we can load any version of the same class inside our application with the help of “slot” concept of JBoss Modules.

Step-5). Now we will need to write a file with name “module.xml” inside the directory “/home/userone/CustomModuleTest/aaa/bbb/1.0” as following:

Step-6). Now we will need to write another file with name “module.xml” inside the directory “/home/userone/CustomModuleTest/aaa/bbb/main” as following:

***NOTE*** If we have the same Jars of different versions defined as part of a module then the Jar which is present inside the “main” directory of the module will be utilized by default until the application uses “META-INF/jboss-deployment-structure.xml” or “WEB-INF/jboss-deployment-structure.xml” to mention which “slot” (version) it want to use.

Step-7). Now it’s turn to compile the Test.java class. So open a shell prompt and then make sure that your PATH variable is set properly to point to the JDK bin directory as following:

Step-8). In the abobe shell prompt now move inside the directory “/home/userone/CustomModuleTest/aaa/bbb/main” to compile the Test.java program and to create a Test1.2.jar file as following:

Step-9). Similarly we wiill compile the Test.java present inside the “/home/userone/CustomModuleTest/aaa/bbb/1.0”. So in the abobe shell prompt now move inside the directory “/home/userone/CustomModuleTest/aaa/bbb/1.0” to compile the Test.java program and to create a Test1.0.jar file as following:

Step-10). Now just copy and paste your custom module directory “aaa” directory placed inside the “/home/userone/CustomModuleTest” to destination directory “/home/userone/jboss-as-7.1.1.Final/modules”

Step-11). Now restart your JBossAS7 server as following:

Testing the Custom Module and it’s slot:

Now we are going to develop a simple web application which will demonstrate how we can load the module, which has name “aaa.bbb” inside our application. And how to load various versions of the same class “aaa.bbb.Test” with the help of “slot” using “WEB-INF/jboss-deployment-structure.xml”

Step-12). Just create a WebApplication directory “TestCustomModule.war” somewhere in your file system like inside “/home/userone/CustomModuleTest”

Step-14). Write the following kind of simple “index.jsp” page inside our Web Application directory “/home/userone/CustomModuleTest/TestCustomModule.war”

Jboss Global Module Slot

Step-15). Create another directory “WEB-INF” as “/home/userone/CustomModuleTest/TestCustomModule.war/WEB-INF” and then palce the following kind of “web.xml” file inside it :

Step-16). Create another file with name “jboss-deployment-structure.xml” inside “/home/userone/CustomModuleTest/TestCustomModule.war/WEB-INF”, Now with the help of this file we will specify which version of the “aaa.bbb.Test ” class we want to use in our application.

Step-17). Copy and paste the “TestCustomModule.war” directory inside your JBossAS7 standalone deployment directory “/home/userone/jboss-as-7.1.1.Final/standalone/deployments”

Step-18). Now write a file with name “TestCustomModule.war.dodeploy” inside the JBoss deployment directory “/home/userone/jboss-as-7.1.1.Final/standalone/deployments” to tell JBoss AS7 to deploy our application. (NOTE: as our application is Exploaded directory so we need to create this file otherwise war/jar/ear “FILES” are automatically deployed without creating *.dodeploy file.)

Step-19). Access the application as “http://localhost:8080/TestCustomModule/index.jsp” to see if your JSP file is able to access the “aaa.bbb.Test” class or not? In the JBoss Console (command prompt output/STDOUT) you will see following kind of output.

Further Testing & Verification :

Step-20). At the time of application deployment based on the version of module which you mentioned in your “jboss-deployment-structure.xml”, If your module is loaded and deployed successfully then you will see a file with name “Test1.0.jar.index” or “Test1.2.jar.index” name inside the “/home/userone/jboss-as-7.1.1.Final/modules/aaa/bbb/1.0” or “/home/userone/jboss-as-7.1.1.Final/modules/aaa/bbb/main”