Can't get version based downloads to work

Question

I am new to JNLP and trying to get version based downloads to work. I have read everything I can find, but I still seem to be missing something. My setup:
Tomcat 4.1.18 (running in JDK 1.4.0)
Java WebStart 1.2
Win 2k
files in .war
-launch.jnlp
-+1.0
|-testapp.jar
|-version.xml
-+images
|-Save.gif
-+META-INF
|-MANIFEST.MF
-+WEB-INF
|-+lib
| |-jnlp-servlet.jar
|-web.xmllaunch.jnlp
TS: 2002-04-23 19:21:05
<?xml version="1.0" encoding="UTF-8"?>
<jnlp codebase="$$codebase" href="$$name">
   <information>
      <title>ljtest 1</title>
      <vendor>Lance</vendor>
      <description>just an example</description>
      <icon href="images/Save.gif"/>
   </information>
   <resources>
      <j2se version="1.2+"/>
      <jar href="1.0/testapp.jar" version="1.0"/>
   </resources>
   <application-desc main-class="Main"/>
</jnlp>version.xml
<jnlp-versions>
   <resource>
      <pattern>
         <name>testapp.jar</name>
         <version-id>1.0</version-id>
      </pattern>
      <file>testapp.jar</file>
   </resource>
</jnlp-versions>web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
    "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
  <web-app>
     <servlet>
        <servlet-name>JnlpDownloadServlet</servlet-name>
        <servlet-class>com.sun.javaws.servlet.JnlpDownloadServlet</servlet-class>
        <init-param>
           <param-name>logLevel</param-name>
           <param-value>DEBUG</param-value>
        </init-param>
     </servlet>
     <servlet-mapping>
        <servlet-name>JnlpDownloadServlet</servlet-name>
        <url-pattern>*.jnlp</url-pattern>
     </servlet-mapping>
  </web-app>Things I have discovered (possibly in error?):
1) I do not need to include the jaxp.jar and parser.jar files because I am using JDK 1.4
2) I do not need to change my testapp.jar to testapp_V1.0.jar because I have included the the version.xml file in the 1.0 directory
I keep getting the following error in WebStart when I loadup the jnlp:
JNLPException[category: Download Error : Exception: null : LaunchDesc: null ]
     at com.sun.javaws.cache.DownloadProtocol.doDownload(Unknown Source)
     at com.sun.javaws.cache.DownloadProtocol.getDownloadSize(Unknown Source)I can get everything to work without version based downloads. Does anyone have any clue what I am doing wrong?
Lance

Answer 1

I found my own error. After loading up sun's reference implementation server in NetBean's debugger I noticed that it was only handling .jnlp files. Going back to the "Packaging JNLP Applications in a Web Archive" document I found my mistake. My web.xml files should have looked like this.
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
    "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
  <web-app>
     <servlet>
        <servlet-name>JnlpDownloadServlet</servlet-name>
        <servlet-class>com.sun.javaws.servlet.JnlpDownloadServlet</servlet-class>
        <init-param>
           <param-name>logLevel</param-name>
           <param-value>DEBUG</param-value>
        </init-param>
     </servlet>
     <servlet-mapping>
        <servlet-name>JnlpDownloadServlet</servlet-name>
        <url-pattern>*</url-pattern>
     </servlet-mapping>
  </web-app>The difference being the <url-pattern> tag. It now tells the web server to handle all files not just .jnlp.
This allowed me to download version based jnlp entries. I still can't get jarDiff things to work, but I will keep banging my head against the wall till I figure that out.
Lance