SAX-core proposal #1: class loading

[David Brownell <david-b@pacbell.net>]

This seems to me most like a bugfix, but I'm sending it for
possible discussion in case anyone has issues.

Class Loading

- JDK 1.2 added a notion of chained class loaders, where loaders
  can try to load from a "parent" that may not be shared with
  every other class in the sytem.

- Implementations of factory helper classes (XMLReaderFactory,
  ParserFactory) don't pass a class loader to Class.forName(),
  so they always use the system class loader.  They could use
  a more intelligent default, at least on JDK 1.2 systems:

    Thread.currentThread ().getContextClassLoader ()

  That way, for example, application code wouldn't need to
  have the parser always live in the system class path.

  Interfaces to those helper classes don't pass the loader (and
  normally shouldn't), so applications using the factory classes
  can't work around that issue themselves.

PROPOSAL:

    - Clarify the javadoc to say that while the system class
      loader is consulted, other appropriate ones may also
      be used.  That will allow JDK 1.2 (and later) based
      factories to use the context's class loader.  

    - Use the (package private) NewInstance.java loader support 
      from the Crimson tree, portably fixing this implementation
      issue for everyone.  (Except for needing a JDK 1.2 compatible
      build environment ...)  This is seemingly public domain since
      there's no copyright...

[ Mentioned by Miles Sabin; happened across the fix in Crimson ]