J2SE Version (please include all output from java -version flag):
  java version "1.6.0-rc"
  Java(TM) 2 Runtime Environment, Standard Edition (build 1.6.0-rc-b65)
  Java HotSpot(TM) Client VM (build 1.6.0-rc-b65, mixed mode, sharing)

Does this problem occur on J2SE 1.4.x or 5.0.x ? Yes / No (pick one)
  Yes

Operating System Configuration Information (be specific):
  Microsoft Windows 2000 [Version 5.00.2195]

Hardware Configuration Information (be specific):
  Pentium 4

Bug Description:
  java.util.Properties should extend Hashtable<String,String> not Hashtable<Object,Object>

  All the methods are implemented using Strings and all the documentation says that the
  keys and values must be Strings.