8004963: URLConnection, downgrade normative reference to ${java.home}/lib/content-types.properties

[Alan Bateman]

As part of preparing for modules in the future [1], we need to look at 
configuration (and other) files in the JDK to see whether such files 
could eventually move to module-private locations.

One of the normative references to a file in ${java.home} is 
URLConnection where it specifies the location of the JDK's 
default/built-in MIME table map. I don't think I've ever come across 
anyone changing that file and thinking about, I don't think I've 
actually come across code using getFileNameMap either. In any case, I 
would like to propose that we remove the reference to this location. If 
anyone really wants to override the file then they can do so with the 
content.types.user.table property. I don't propose any implementation 
changes, the implementation will continue to look at the default file as 
before. The webrev with the changes is here:

http://cr.openjdk.java.net/~alanb/8004963/webrev/

Note that I've used the opportunity to remove a paragraph from the class 
description that refers to a field that was removed in JDK1.1.6. I don't 
think this is needed anymore.

Thanks,
Alan

[1] http://openjdk.java.net/jeps/162