first unzip the .jar
cg$ unzip javatest3.jar
Archive: javatest3.jar
creating: META-INF/
inflating: META-INF/MANIFEST.MF
inflating: SiteError.class
inflating: evil.class
...
from there use jad to decompile
cg$ ./jad -r -ff -s java javatest/SiteError.class Parsing javatest/SiteError.class... Generating SiteError.java
thats it, now you can read the code.
