Message4488

This is for the security policy in the Google App Engine.  It can
roughly be recreated by forbidding all write access to disk and read
access outside the working directory (which makes some
File.isDirectory() checks fail).  The additional changes are because
SecureClassLoader and Compiler are not on the JRE whitelist. 
Compiler.compileClass() is documented to be a no-op, so I do not think
removing it is an issue.  URLClassLoader should work just as well as
SecureClassLoader.