Message9250

So Jython does do package analysis of the JDK, much as for any other jar. So when running Jython for the first time, you should see such output similar to what's below:

...
*sys-package-mgr*: processing new jar, '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/resources.jar'
*sys-package-mgr*: processing new jar, '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/rt.jar'
*sys-package-mgr*: processing new jar, '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/jsse.jar'
*sys-package-mgr*: processing new jar, '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/jce.jar'
*sys-package-mgr*: processing new jar, '/Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/charsets.jar'
*
...

Through Java 8, the key package here is rt.jar, which contains core Java packages like java.util.Arrays, as can be readily seen by running the jar tf command:

$ jar tf /Library/Java/JavaVirtualMachines/jdk1.7.0_21.jdk/Contents/Home/jre/lib/rt.jar | grep Arrays
java/util/Arrays$LegacyMergeSort.class
java/util/Arrays$ArrayList.class
java/util/Arrays.class

If this package scanning cannot be done, then the problems of #1383 arise, regardless of whether it is builtin or not.

Let's double check this package scanning occurred, in the right place.