Web Start unable to load external driver

Question

I have a project as Java application, and it was running fine until I made it into web start. My project relies on external library to deal with serial port and USB port.

To run this app. in DOS command:

java -DPropLoc=Drivers.Properties -jar myprog.jar <args>

In Netbeans 6.7.1 JRE 1.6u21, When select WebStart as Project Configuration, I can run the the main project but it failed to load the driver. In the Project Properties, I have the VM Option set to -DPropLoc="Drivers.Properties and the driver relies on this file. But if I do debug and with step by step, it will load the driver and thing run OK.

What is the problem with the web start launch?

This is the error I got after loading the driver:

Caught java.lang.NullPointerException: name can't be null while loading driver com.sun.comm.Win32Driver
javax.comm.NoSuchPortException at javax.comm.CommPortIdentifier.getPortIdentifier(CommPortIdentifier.java:105)

Since I don't understand why it loaded the driver when debugging in NB step by step. But by running the main project by pressing F6, it won't load the driver. What is the difference of environment or JVM between Debug and Run.

Below is launch.jnlpfile:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<jnlp codebase="file:/C:/bit9prog/dev/NetBeansProjects/MyProg/dist/"  href="launch.jnlp" spec="1.0+">
<information>
    <title>MyProg</title>
    <vendor></vendor>
    <homepage href=""/>
    <description>MyProg</description>
    <description kind="short">MyProg</description>
<offline-allowed/>
</information>
<security>
<all-permissions/>
</security>
<resources>
<j2se version="1.6+"/>
<property name="PropLoc" value="Drivers.Properties"/> 
<jar eager="true" href="MyProg.jar" main="true"/>
<jar href="lib/comm.jar"/>
<jar href="lib/config.jar"/>
<jar href="lib/jakarta-regexp-1.4.jar"/>
<jar href="lib/log4j-1.2.14.jar"/>
<jar href="lib/swing-layout-1.0.jar"/>
<jar href="lib/trove.jar"/>
<jar href="lib/XmlUtil.jar"/>
</resources>
<application-desc main-class="MyProg">
<argument>r</argument>
<argument>.</argument>
</application-desc>
</jnlp>

Answer 1

This is a security issue. Because your driver is doing native access it has to be signed, and if the driver is already signed then the way that you add it to your jnlp file is slightly different.

For example with an internal library that is signed using your certificate then the entry look as follows

        <jar href="myLibrary.jar"/>

However for a resource that is signed by somebody else your entry looks like so

<extension href="Driver.jnlp" name="Driver" version=""/>

And it needs its own JNLP file

<?xml version="1.0" encoding="utf-8"?>
<jnlp spec="1.0+"
codebase="{yourcodebase}" href="Driver.jnlp">
    <information>
        <title>Driver</title>
        <vendor>Driver Corporation</vendor>
    </information>
    <resources>
        <jar href="lib/TheExternalDriver.jar"/>
    </resources>
    <security>
        <all-permissions/>
    </security>
    <component-desc/>
</jnlp>