maintain classpath in more elementary manner: turn ISABELLE_CLASSPATH into -classpath option, so that all jars are covered by sun.misc.Launcher.AppClassLoader (e.g. relevant for loading add-on resources);
ignore $ISABELLE_JAVA_EXT -- do not change java.ext.dirs;
#main components for everyday use, without big impact on overall build time
cvc3-2.4.1
e-1.8
exec_process-1.0.3
Haskabelle-2013
jdk-7u25
jedit_build-20130910
jfreechart-1.0.14-1
kodkodi-1.5.2
polyml-5.5.0-3
scala-2.10.2
spass-3.8ds
z3-3.2
xz-java-1.2-1