Question

After finally solving the jar signing problem (thank you everyone for your help!), a new one has now come up.

When trying to launch the web start app from the launch.jnlp file I get the following error :

java.lang.NullPointerException
at com.sun.javaws.Launcher.executeApplication(Unknown Source)
at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
at com.sun.javaws.Launcher.doLaunchApp(Unknown Source)
at com.sun.javaws.Launcher.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

If I use the jnlp file that points to the jar file on my computer, the app runs fine, but if I try to use the jar file in the website – I get the above error.

What exactly is the problem?

The jnlp file has the right format, otherwise why would it work on my local jar file?

Here is the jnlp:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<jnlp spec="1.0+">
    <information>
        <title>ExcelReader</title>
        <vendor>Adam</vendor>
        <homepage href="http://www.appquad.com"/>
        <description>ExcelReader</description>
        <description kind="short">ExcelReader</description>


    <offline-allowed/>
  </information>
    <update check="background"/>
    <security>
<all-permissions/>
</security>
    <resources>
       <j2se version="1.7+"/>
       <jar href="http://www.appquad.com/ExcelCopyApp/sExcelReader.jar" main="true"/>
       <jar href="http://www.appquad.com/ExcelCopyApp/lib/jxl.jar"/>
     </resources>
     <application-desc main-class="excelreader.ExcelCopyApp">

     </application-desc>
    </jnlp>

Answer 1

Be sure that your JNLP file has the right format: http://download.oracle.com/javase/6/docs/technotes/guides/javaws/developersguide/syntax.html