I have attached a loader.tar.gzip that contains a simple test program
and a couple jar files.

From the comment in JarFileTest.java:

/*
 * It seems the URLClassLoader is not locating classes from the
 * jar file's Class-Path attribute.
 *
 * I have foo.jar contain Foo.class, which has a dependency on Bar.class
 * which is contained in Bar.jar. The maniofest file for foo.jar has
 * the attribute Class-Path: bar.jar
 *
 * I create a URLClassLoader with the url array containing just the URL
 * to foo.jar.
 *
 * I get a NoClassDefFoundError for Bar.class, when I try an instantiate
 * Foo.class (I thought the URLClassLoader was supposed to define the classes
 * from the union of the url array in the URLClassLoader's constructor with
 * the jars listed in the Class-Path attribute.
 *
 * If I add bar.jar to the url array to the URLClassLoader constructor, all is ok.
 *
 * Must we (JWS/JS) analyze the jar hierarchy prior to cretaing a URLClassLoader?
 * This would contradict the claim in the spec:
 * http://java.sun.com/products/jdk/1.2/docs/guide/extensions/spec.htm
 *
 */