* gnu/gcj/protocol/jar/Connection.java (getJarFile): download and
cache remote jar files.
* gnu/gcj/runtime/VMClassLoader.java: Don't construct jar URL, only
add File.separator to URL when it is a directory.
* java/lang/ClassLoader.java: Add Classpath javadoc.
(parent): final.
(getParent): Add (disabled) security check.
(findLibrary): New default method.
* java/net/JarURLConnection.java (getManifest): Implement.
(getInputStream): Only create InputStream when entry exists.
(getHeaders): Only use jarFileURLConnection or JarEntry to set length
when they exist.
* java/net/URLClassLoader.java: New/Rewritten version from Classpath.
From-SVN: r59949
