Exception error while running a JavaFX2 app with CSS - css

Question

I am making a text editor app in JavaFX2 on NetBeans. My problem is this: whenever I try to insert the line scene.getStylesheets().add(<classname>.class.getResource("<css file>.css").toExternalForm()); to link the css, and run it, it shows an error: "Exception while running Application"What exactly is this exception? I've tried removing this line, and then the app runs smoothly. Just five-six hours back, I had inserted this same line of code (with correct classes and css file), it was easily able to use the css. But now, I've created another 3 projects to check it, but the app shows the same error and gets removed on removing this code. I create the Css by right-clicking the Source-packages icon > new > Cascading Style Sheets. I fill in all the correct classes and location for css file, yet this happens. Also tried Shift + F11 (clean and rebuild). When I launch the older app(with css), it runs without an error. (BTW I use Win8 Pro x64, if u need it)The output panel stops at Executing com.javafx.main.Main from <location>\Qwerty.jar using platform C:\Program Files\Java\jdk1.7.0_17/bin/java and then shows error:
Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.javafx.main.Main.launchApp(Main.java:642)
at com.javafx.main.Main.main(Main.java:805)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:403)
at com.sun.javafx.application.LauncherImpl.access$000(LauncherImpl.java:47)
at com.sun.javafx.application.LauncherImpl$1.run(LauncherImpl.java:115)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NullPointerException
at qwerty.Qwerty.start(Qwerty.java:36) (LINE 36 is where the reference to css is)
at com.sun.javafx.application.LauncherImpl$5.run(LauncherImpl.java:319)
at com.sun.javafx.application.PlatformImpl$5.run(PlatformImpl.java:215)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:179)
at com.sun.javafx.application.PlatformImpl$4$1.run(PlatformImpl.java:176)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl$4.run(PlatformImpl.java:176)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
... 1 more
Java Result: 1

Answer 1

The issue is explained in the nested excpetion:
Caused by: java.lang.NullPointerException
at qwerty.Qwerty.start(Qwerty.java:36) (LINE 36 is where the reference to css is)
Check if <classname>.class.getResource("<css file>.css") is null. Maybe you're specifing the wrong path or the css is not in the jar?