java.util.regex.Matcher and StringBuilder/StringBuffer APIs

[Robert Marcano]

Greetings. Is there a reason the newest APIs added to Matcher 
(performance maybe?) with StringBuilder arguments weren't added as 
Appendable instead?

For example:

   public StringBuilder appendTail(StringBuilder sb)
   public Matcher appendReplacement(StringBuilder sb, String replacement)

Could have been:

   public <T extends Appendable> T appendTail(T ap)
   public Matcher appendReplacement(Appendable ap, String replacement)

Both appendReplacement(...) implementations are copies, that could be 
reduced to a simple one if Appendable was the argument, and the present 
ones calling to that.

If this sounds reasonable, I could write a patch for testing.

Note: I was hit with this when trying to use another kind of Appendable 
optimized for my use case.