I did a bit more testing. You can create a default JavaFX application NetBeans, erase *all* the code from it so that all you've got left is your Application class that does nothing, then try to launch it with the JNLP file that *Netbeans creates for you* and it *still* will give you that NullPointerException when you try to launch it!
Furthermore, this seems related to the following issues, which still have not been resolved:
Unless I'm missing something, it appears to be that Oracle has made it COMPLETELY IMPOSSIBLE to launch a JavaFX application through Web Start in update 25, and after several weeks of this problem, still NOTHING has been done about it! WTF?! Am I going crazy? Can someone help me out here?
It's the JNLP that Netbeans automatically generates for you when building a JavaFX project. It used to run the jar (in the same directory) just by double-clicking it after creating a project, but no longer does. Anyhow, here it is:
<?xml version="1.0" encoding="utf-8"?>
<jnlp spec="1.0" xmlns:jfx="http://javafx.com" href="TestLaunch.jnlp">
<description>Sample JavaFX 2.0 application.</description>
<jfx:javafx-runtime version="2.2+" href="http://javadl.sun.com/webapps/download/GetFile/javafx-latest/windows-i586/javafx2.jnlp"/>
<j2se version="1.6+" href="http://java.sun.com/products/autodl/j2se"/>
<jar href="TestLaunch.jar" size="17987" download="eager" />
<applet-desc width="800" height="600" main-class="com.javafx.main.NoJavaFXFallback" name="TestLaunch" >
<param name="requiredFXVersion" value="2.2+"/>
<jfx:javafx-desc width="800" height="600" main-class="testlaunch.TestLaunch" name="TestLaunch" />