classpaths with whitespaces do not work when compiling java jobs on the fly

If the classpath has whitespaces (e.g. "c:\Program Files\scheduler\lib") the call to javac will not quote or escape these.
Hence javac will treat strings after the whitespaces as additional arguments.

javac: invalid flag: lib\activation.jar;c:/scheduler.al/new
16:20:28.218 scheduler 0 2388.B88 672.250MB Usage: javac <options> <source files>
16:20:28.218 scheduler 0 2388.B88 672.250MB where possible options include:
...