Basics of Web Start and Demo 1

Hey Guys, I am working on the research and development on whether we can use Java Web Start in our project or not. So here are my findings till now with practical as I have already posted demo as well.

Java Web Start is a platform designed by the Sun for running java applications from the browsers.

The requirement on which I am working is whether we can handle automatic update or also only the one jar update out of multiple jars which really has code change or any other update. Version management and few others.

JWS (Java Web Start) can run on any platform, so it’s a cross platform.

We can handle memory, heap and other parameters through JWS.We can bundle multiple jars of a project and execute JNLP file (will explain) to download all those jars on local system to speed up the frequent application access. If there is any change in the project or in any jar or configuration file, we can handle it and can download only changed jar or file from the server by changing our JNLP file.

JNLP is Java Network Launching protocol and can be used for web start. It’s an XML file with configuration settings for our java application. It has XML schema which specify that how we can execute or launch our java application.

For our browser or the server on which we are running JNLP, to recognize this file we need to set MIME type application/x-java-jnlp-file. For example to make it recognized by the Web Sphere server we need to add MIME type as mentioned below.

and then add jnlp extension

JNLP features:

1.       Includes .jar file path and main class name

2.       The way server is configured, we can also configure if browser is not configured and execute jnlp which will download applicaition. We need to configure server or browser because it will pass jnlp to JRE.

3.       We can create a jnlp which will check JRE or its version to run application or even prompt user to install appropriate jre.

4.       After execution, user don not neet to be get connected to internet.

5.       Updates automatically gets downloaded when user will get connected to interbet and version handling will be handled automatically if JNLP is properly configured.

JNLP file: (jar versioning and argument passing to main method)

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE jnlp PUBLIC "-//Sun Microsystems, Inc.//DTD JNLP 1.5//EN" "http://www.netbeans.org/jnlp/DTD/jnlp.dtd">

<jnlp codebase="http://localhost:8080/examples/" href="Test.jnlp">

  <information>

    <title>test</title>

    <vendor>test.com</vendor>

   

    <description>Test</description>

   

    <offline-allowed/>

   <!-- Prefer a shortcut for online operation -->

<shortcut online="true">

  <!-- create desktop shortcut -->

  <desktop/>

  <!-- create menu item for this app under the major heading Esperanto -->

  <menu submenu="AAA"/>

</shortcut>

  </information>

 <resources>

          <j2se version="1.7+"  />

          <jar href="Test.jar" main="true" version="1.0"/>

          <jar href="SwingDemo.jar" version="1.0"/> 

                 <jar href="Hello.jar" version="1.3"/>

                 <jar href="World.jar" version="1.0"/>

           <property name="java.home" value="C:\Program Files\Java\jdk1.8.0_101\"/>                

          <property name="jnlp.versionEnabled" value="true"/>

          

     </resources>

  <application-desc main-class="com.sks.test.Test">

              <argument>John</argument>

              <argument>http://localhost:8080/examples/test.cfg</argument> 

  </application- desc>

</jnlp>

JNLP file (jar version and configuration version)

<?xml version="1.0" encoding="utf-8"?> <!-- JNLP File for Web Start Demo -->

<jnlp codebase="http://170.197.229.152:8080/deployment " href="">

       <security>

              <all-permissions />

       </security>

       <information>

              <title>Swing Application - Test</title>

              <vendor>Sharma</vendor>

              <description>Swing Application - Test</description>

              <description kind="short">Swing Application - Test</description>

              <offline-allowed />

       </information>

       <resources>

              <j2se version="1.7+" />

              <jar href="http://<IP>:8080/examples/Test.jar" main="true"

                     version="9" />

              <jar href="http://<IP>:8080/examples/conf.jar" version="1.1" />

              <property name="jnlp.versionEnabled" value="true" />

       </resources>

       <application-desc main-class="com.sks.test.Test">

              <argument>test</argument>

       </application-desc>

</jnlp>

Demo 1.

    1.       Below screen showing Java Swing application or you can create any Java application.

    2.       Configured JNLP file to download multiple jars through link mentioned in green circle:

       3. Exporting Java project as a Test.jar

     4.       Providing main entry class while generating jar file

    

     

Store jar file to D:\apache-tomcat-7.0.72\webapps\examples location on web server.

  5. Sign this jar as per jar signing process mentioned above in the document. 

  6. Rename it for versioning eg. Test__V1.0.jar and SwingFileDownloadHTTP__V1.0.jar

      7. Update JNLP file with below line,

   <jar href=" Test.jar" main="true" version="1.0" />

   <jar href=" SwingFileDownloadHTTP.jar" main="true" version="1.0" />

       SwingFileDownloadHTTP__V1.0

    8. Creating web link to run this file.

9  9. JSP file to run JNLP file

   

a   run on server.

    10. After clicking on JNLP Run hyper link, you will be able to see your java application running through web start.

      

   11.       Checking download and versioning..

    Go to Control Panel à Java à View

        

    12. The jar which was configured in build path gets downloaded.

     

     Thanks !!! Keep learning, keep sharing !!!