My source file is
0 0 * * * java -classpath .../MyDir/proj/ myProj
Exception in thread "main" java.lang.NoClassDefFoundError: com/gargoylesoftware/htmlunit/WebClient
Something like this:
0 0 * * * java -classpath .../MyDir/proj/:.../MyDir/proj/library/jar1.jar:.../MyDir/proj/library/jar2.jar myProj
or if you are using a recent JVM you can use a wildcard to match all of the JAR files.
0 0 * * * java -classpath .../MyDir/proj/:.../MyDir/proj/library/\* myProj
(The backslash is probably unnecessary because 'globbing' is unlikely to match anything in that context ...)
Better still, put the command (and any others that need to be run to prepare for the launch) into a shell script, and run the script from your crontab entry instead.