The RPC refactoring for issue 389 which was committed at r677 contained a couple of Java 1.5 only features.  This patch makes the RPC code compliant with the 1.4 JRE.  All unit tests passed.

Review by: scottb



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@686 8db76d5a-ed1c-0410-87a9-c151d255dfc7