Special case JDK9+ URLClassLoader url resource loading

'#' sign represents URL fragment and is not valid URL path element.

As per spec it is not allowed for it to be a part of path and instead must be URL encoded.

So for example for file in location in UNIX systems: "/Users/piotrklimczak/test#", the valid URL encoding to load it in Java is:

new File(new URL("file:///Users/piotrklimczak/test%23").toURI()) 

Works.

While

new File(new URL("file:///Users/piotrklimczak/test#").toURI()) 

Returns java.lang.IllegalArgumentException in Java: URI has a fragment component

FELIX-6326 effectively allows '#' to be accepted as valid URL path element, which in turn breaks JDK9+ URLClassLoader which is using URL fragment (ref) to deal with multi-release jars.

This then breaks pax-transx-tm-narayana installation in Karaf 4.3.1 (which uses URLClassLoader).

In my opinion FELIX-6326 should be reverted and users should be encoding special characters correctly in their resource paths as per above example.

I've taken a risk to mark it as a blocker as effectively it blocks using Narayana TM, rendering Karaf 4.3.1 not usable for us.
Feel free to downgrade it if my judgement failed here.