Paths in the "jrt:/" NIO filesystem are currently of this form:

  /$MODULE/$PATH

where $MODULE is a module name (e.g., "java.base") and $PATH is the name
of a resource, most often the binary name of a class.

Let's add a directory level, and support two forms:

  /modules/$MODULE/$PATH
  /packages/$PACKAGE/$MODULE

where $PACKAGE is a package name (e.g., "java.lang"). A path of the
second form names a symbolic link which, in turn, points to the
directory under /modules that contains a module that defines that
package. Example:

  /packages/java.lang/java.base -> /modules/java.base

To find java/sql/Array.class without knowing its module you look up
/packages/java.sql, which is a directory, and enumerate its entries.
In this case there will be just one entry, a symbolic link named
"java.sql", which will point to /modules/java.sql, which will contain
java/sql/Array.class.

The reason for having /package/$PACKAGE be a directory of symbolic links
to module directories rather than such a symbolic link itself is that in
some scenarios multiple modules can contain packages of the same name.