What should I do if I encounter an UnsupportedClassVersionError using WindowBuilder?
An UnsupportedClassVersionError is usually caused by attempting to run code compiled against a later JRE with an IDE using an earlier JRE. Typically, you will see this when trying to use a class (such as a custom widget) that has been compiled against JDK 1.5 within a version of Eclipse launched with JDK 1.4. Two solutions are possible: you may either recompile the class using JDK 1.4, or you can tell Eclipse to run using JDK 1.5 by modifying its startup parameters as follows (use your path to JDK 1.5 on your system): -vm C:\jdk1.5.0_04\bin\java.
