Add custom classloaders to compilation classpath: "javac -J-Djava.system.class.loader=my.custom.ClassLoaderImpl theSource.java" http://forums.java.net/jive/thread.jspa?messageID=87728&tstart=0#87728 Possible NULL from static fields... which is documented behaviours - http://qaix.com/java-programming/575-882-puzzling-class-field-hellip-read.shtml Comparing Class.getResourceAsStream() and bundle.getEntry(), point out some issues of using Class.getResourceAsStream() - http://www.eclipsezone.com/eclipse/forums/t101557.rhtml Basic of classloader - http://www.journaldev.com/349/java-interview-questions-understanding-and-extending-java-classloader http://java.sun.com/developer/technicalArticles/Networking/classloaders/