NoSuchMethodError: getScaleFactor error on OS X with 1.7.0_40-b43

Question

I am having problems with JavaFX applications running on OSX under Java 1.7 u40. Has anyone else seen this error, and have a solution?
Exception in thread "main" java.lang.RuntimeException: java.lang.NoSuchMethodError: getScaleFactor
  at com.sun.javafx.tk.quantum.QuantumToolkit.startup(QuantumToolkit.java:281)
  at com.sun.javafx.application.PlatformImpl.startup(PlatformImpl.java:122)
  at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:163)
  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:724)
Caused by: java.lang.NoSuchMethodError: getScaleFactor
  at com.sun.glass.ui.mac.MacApplication._initIDs(Native Method)
  at com.sun.glass.ui.mac.MacApplication.<clinit>(MacApplication.java:34)
  at com.sun.glass.ui.mac.MacPlatformFactory.createApplication(MacPlatformFactory.java:33)
  at com.sun.glass.ui.Application.Run(Application.java:103)
  at com.sun.javafx.tk.quantum.QuantumToolkit.startup(QuantumToolkit.java:271)
  ... 5 more
I am running under  OSX 10.8.4. If I fallback to u7 I have no problems.

Answer 1

In Java 1.7, the JavaFX runtime (jfxrt.jar) is shipped with the JDK but is not on the classpath by default. You probably copied it into /Library/Java/Extensions at some point in order to avoid having to set the classpath while developing and running your JavaFX applications.
This probably isn't the best idea, for exactly the reason you just came across: it won't get updated when you update your JRE/JDK, so you have to remember to update that file every time you update the JDK. It might be better to configure your IDE to create JavaFX projects which know how to set the classpath (use E(fx)clipse or NetBeans, for example) and configure builds that create correctly-deployed JavaFX applications (i.e. with jfxrt.jar bundled in).
Note that in JDK 8, JavaFX is a full member of the core library, so jfxrt.jar is on the classpath by default.