Java libraries packages *may* add a sympolic link from
/usr/share/java/ext/packagename[-extraname].jar to
/usr/share/java/packagename[-extraname]-fullversion.jar.
In 2.1 Virtual machines:
If a virtual machine has a mechanism to search the jars
in one or more "extensions directories", it *should* use
/usr/share/java/ext as the default such directory.
In 2.2 Java compilers:
If a Java compiler has a mechanism to search the the jars
of one or more "extensions directories", it *should* use
/usr/share/java/ext as the default such directory.