Prepare the Application Client run-time dependency component for Java Web Start

Prepare the Application Client run-time dependency component for Java Web Start

For a J2EE application client application and or Thin application client application to be launched using Java Web Start (JWS), an Java Runtime Environment that IBM provides, the library JAR files and properties files bundled in Application Client for WAS must be installed in the JWS. This article provides the steps to build the Application Client run-time dependency component from an Application Client installation. It is packaged as a Web Archive Resource (WAR) file that can be installed in an Application Server. Install the Application Client for WAS for the platform to which the client application deploys. If there is a requirement to deploy the client application to multiple platforms, the Application Client run-time dependency component must be built separately for each platform that client application supports.

For example, if the client application deploys to both the Windows platform and Linux platform, follows the steps for this task to build the Application Client run-time dependency component for Windows on a Windows platform machine with the Application Client for WAS for Windows installed. Now, repeat the steps for this task to build the Application Client run-time dependency component for Linux on a Linux platform machine with the Application Client for WebSphere Application Server for Linux installed.

Procedure
Install the Application Client for WAS for the client application supported operating systems.

Install Application Client in the C:\Program Files\IBM\WebSphere\AppClient directory.
Change the directory to the installation bin directory.
For example:
CD C:\Program files\IBM\WebSphere\AppClient\bin
Run the buildClientRuntime tool to generate the Application Client run-time JAR file in a temporary directory which contains the Java 2 Runtime Environment, Application Client run-time properties, the SSL KeyStore and TrustStore file, and the Application Client run-time library JAR files.
For example, if you are using version 6.1:
buildClientRuntime C:\WebApp1\runtime\WASClient6.1_windows.jar 
If you are building an Application Client run-time JAR file only for serving Thin application client applications and not for J2EE application client applications, you can reduce the size of the generated JAR file by not including the Application Client run-time library JAR files. An extra parameter is passed to the buildClientRuntime tool.
For example, if you are using version 6.1:
buildClientRuntime C:\WebApp1\runtime\WASClient6.1_windows.jar 
                   buildThin
Copy the WebSphereClientRuntimeInstaller.jar file to the same location of the JAR file generated in the previous step. This JAR file is located in the JWS directory of the WAS clients installation.
For example:
copy ..\JWS\WebSphereClientRuntimeInstaller.jar   C:\WebApp1\runtime
Sign the JAR files created from the previous steps, using the Java 2 SDK jarsigner utility.
For example, if you are using version 6.1:
cd C:\WebApp1\runtime
 jarsigner -keystore myKeystore -storepass myPassword 
                WASClient6.1_windows.jar myKeyAliasName
 jarsigner -keystore myKeystore -storepass myPassword 
                WebSphereClientRuntimeInstaller.jar myKeyAliasName
This step also requires you to create a keystore file, such as myKeystore.
You must also create a self-signed certificate for the myKeystore file.
When running the JAR signer tool on HP platforms, add the -J"-Xmx256m" flag to the jarsigner command to increase the available heap size and prevent the error, OutOfMemoryError. See the following example for help:
jarsigner -J"-Xmx256m" -keystore myKeystore -storepass myPassword 
                WebSphereClientRuntimeInstaller.jar myKeyAliasName
Create an Application Client run-time installer JNLP descriptor file or a JavaServer Pages file if it is generated dynamically in the same temporary directory as previous step. See the sample JNLP file shown in the Example section of this topic.

Package the two signed JAR files and the Application Client run-time installer JNLP descriptor file into a WAR file. This WAR file is packaged into an EAR file that can be deployed to an Application Server.
Results
Your Web application is ready to serve the Application Client run time and the JRE environment.

Example


<%-- // to set the Last_Modified header so that the JNLP client will know whether to download
     // the JNLP file again and update the cached copy.
     String jspPath = application.getRealPath(request.getServletPath());
     java.io.File jspFile = new java.io.File(jspPath);
     long lastModified = jspFile.lastModified();
%><%    
      // locally declared variables
      String url=request.getRequestURL().toString(); 
      String jnlpCodeBase=url.substring(0,url.lastIndexOf('/'));
      String jnlpRefURL=url.substring(url.lastIndexOf('/')+1,url.length());

      // Need to set a JNLP mime type - if WebStart is installed on the client,
      // this header will induce the browser to drive the WebStart Client
      response.setContentType("application/x-java-jnlp-file");                            1
      response.setHeader("Cache-Control", null);
      response.setHeader("Set-Cookie", null);
      response.setHeader("Vary", null);
      response.setDateHeader("Last-Modified", lastModified);

      // An installer must reply with the version number for a given install
      if (response.containsHeader("x-java-jnlp-version-id"))
        response.setHeader("x-java-jnlp-version-id", "WASClient6.1.0");               2
      else
        response.addHeader("x-java-jnlp-version-id", "WASClient6.1.0");
%>
     
<?xml version="1.0" encoding="utf-8"?>





<jnlp spec="1.0+"  codebase="http://YOUR_APP_SERVER:PORTNUMBER/WEBAPP_CONTEXT_ROOT/Runtime/WebSphereJre">

<information>
  <title>Application Client Java Runtime Environment</title>
  <vendor>IBM</vendor>
  <icon href="icon.gif"/>
  <description>Application Client Java Runtime Environment</description>
  <description kind="short">Application Client JRE</description>
  <description kind="tooltip">Application Client JRE</description>
  <offline-allowed/>
</information>

<security>
  <all-permissions/>
</security>

  <resources>
    <j2se version="1.4+"/><%-- The installer can use any 1.4 JRE --%> 3
     <jar href="WebSphereClientRuntimeInstaller.jar" main="true"/>  4    

    
    <property name="com.ibm.websphere.client.jre.version" value="WASClient6.1.0"/>  5  
  </resources>

  <resources os="Windows">  6  





      <jar href="WASClient6.1.0_Windows.jar"/>  7  
  



<!-- relative path of the jre executable —->

      <property name="com.ibm.websphere.client.jre.launch.java" 
  value="java\jre\bin\javaw.exe"/>  8  
  
  </resources>
  <installer-desc main-class="com.ibm.websphere.client.installer.ClientRuntimeInstaller"/>
</jnlp>
Specifies that the file is a JNLP mime type so that the browser can process the JNLP file.

Specifies the exact version of this Application Client run-time dependency component in the response by setting the HTTP header field: x-java-jnlp-version-id.

Specifies the required JRE version to run the installer program.

Specifies the installer WebSphereClientRuntimeInstaller.jar file, which contains the ClientRuntimeInstaller class.

Specifies a system property that defines the version of Application Client run-time dependency component. This version is registered to the JNLP client.

Specifies resources for a particular platform. Each supported client application platform needs its own separate JAR file.

Specifies the Application Client run-time dependency component JAR file.

Program to call that starts a JVM for the client application.

What to do next
Preparing Application Client run-time library component for Java Web Start.

buildClientRuntime tool

ClientRuntimeInstaller class

Related concepts

Web applications

Related tasks

Preparing Application Clients run-time library component for Java Web Start