tests/org.eclipse.rap.rwt.testfixture/src/servicehandler.xml

<?xml version="1.0" encoding="UTF-8"?>
<servicehandler>
  <handler 
    class="org.eclipse.rwt.service.ServiceHandler_Test$CustomHandler" 
    requestparameter="org.eclipse.rwt.service.ServiceHandler_Test.CustomHandler" />
</servicehandler>