Chapter 5. Overview of JBoss EAP class loading

• Static modules
• Dynamic modules

• Creating a custom module manually
• Creating a custom module by using the management CLI

• See the Add an Explicit Module Dependency to a Deployment section of the JBoss EAP Development Guide for adding application-specific dependencies using deployment descriptors.

• See the Global modules in JBoss EAP section for instructions on adding modules as dependencies to all applications.

Verification

• Verify that your application can retrieve the properties from one of the properties files contained within the Java archive (JAR).

  Thread.currentThread().getContextClassLoader().getResource("my.properties");

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• Removing a custom module manually
• Removing a custom module by using the management CLI

• Add services="import" to the module in your jboss-deployment-structure.xml

• Add services="true" to the global module definition.

  /subsystem=ee:write-attribute(name=global-modules,value=[{name=module1,services=true}]

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  Or, when adding multiple modules:

  /subsystem=ee:write-attribute(name=global-modules,value=[{name=module1,services=true},{name=module2,services=false}]

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  To add a new module to an existing list:

  /subsystem=ee:list-add(name=global-modules,value={name=module1,services=true})

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• When defining the global module using the management console, make sure that the value of the Services property is On.

• Share multiple libraries across deployed applications.
• Maintain libraries by moving common frameworks, usually added to application libraries, to a common location.

• The path resource loader provides files as a resource to an application.
• The resource loader provides classes, contained in a JAR file, to an application.

Prerequisites

• Create a standard directory on your operating system. This standard directory must contain all the JAR files and resources you need deployed to applications. This creates a directory tree.

  Example of a common directory showing a list of common libraries that were copied to applications

  /my-common-libs/log4j2.xml
  /my-common-libs/libs/log4j-api-2.14.1.jar
  /my-common-libs/libs/log4j-core-2.14.1.jar

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  Note

  Since the server deploys an application and loads the global directory, you cannot configure the global directory to override the server’s library versions. A global directory cannot replace libraries shipped with the server.

Procedure

• Depending on your server setup, use the read-resource operation to read the current values of your global directory configuration.

  Example output of reading the current values of a global directory configuration on a standalone server

  [standalone@localhost:9990 /] /subsystem=ee/global-directory=my-common-libs:read-resource
  {
        "outcome" => "success",
        "result" => {
            "path" => "my-common-libs",
            "relative-to" => "jboss.home.dir"
        }
   }

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  Example output of reading the current values of a global directory configuration on a server in a managed domain

  [domain@localhost:9990 /] /subsystem=ee/global-directory=my-common-libs:read-resource
   {
        "outcome" => "success",
        "result" => {
            "path" => "my-common-libs",
            "relative-to" => "jboss.server.data.dir"
        }
   }

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Procedure

• To remove a global directory from your standalone server, use the following command:

  [standalone@localhost:9990 /] /subsystem=ee/global-directory=my-common-libs:remove()

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• To remove a global directory on a server in a managed domain, use the following command:

  [domain@localhost:9990 /] /profile=default/subsystem=ee/global-directory=my-common-libs:remove()

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• Deployments of Web Archive (WAR) and Java Archive (JAR) files are named using the following format:

  deployment.DEPLOYMENT_NAME

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  For example, inventory.war and store.jar will have the module names of deployment.inventory.war and deployment.store.jar respectively.

• Subdeployments within an Enterprise Archive (EAR) are named using the following format:

  deployment.EAR_NAME.SUBDEPLOYMENT_NAME

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  For example, the subdeployment of reports.war within the enterprise archive accounts.ear will have the module name of deployment.accounts.ear.reports.war.