Unsupported major.minor version 49.0

My understanding of the "Unsupported major.minor version" error is that
you are trying to use a class file compiled with a newer Java version
than your JVM. The strange thing is that 1.5 (by whatever name) is
version 49. So it looks like you have a 1.4 class file, and are running it
with a VM that's older than that.


49 means that it was compiled with a 1.5 JDK. Depending on how it was compiled it may not be usable on a 1.4 JDK. The 1.5 JDK defaults to writing class files that are only compatible with 1.5. To change that, specify the -target option and, perhaps, the -source option. See the javac doc for more information.