Given that only UTF-8 is used, how about an eagerly-initialized RPCServletUtil.UTF8_CHARSET instead? (similar to Guava's Charsets.UTF_8 [1])
[1] http://docs.guava-libraries.googlecode.com/git-history/v10.0.1/javadoc/com/google/common/base/Charsets.html#UTF_8 http://gwt-code-reviews.appspot.com/1588803/ -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
