Handlng character sets in Weblogic

Question

I have a Java application where we do Ajax calls to update screen items. The application is working fine in Eclipse/Tomcat. Where the Ajax call takes a parameter (send with EncodeURIComponent) dos a lookup in the Oracle database and returns a UTF-16 response. This works correctly in the Tomcat environment.
However, when running in the Weblogic environment the parameter that is being sent to the servlet arrives garbled. When I look in our debugging logs on Tomcat the string shows (in the ServletBase class) as a UTF-8 looking string. The same statement in the Weblogic environment shows question marks.
The code that initiates the Ajax request is:
var url = 'JobSearchServlet?clientdata=<%=cd.getId()%>&value=' + encodeURIComponent(param);
              req.open("POST", url, false);
              req.send(null);The code in the ServletBase class (an abstract class that extends HttpServlet) looks like this:
  request.setCharacterEncoding(SystemConfigUtil.getSetting(SystemConfigUtil.DEFAULT_ENCODING, "UTF-8"));
            IUser user = SessionUtil.getUser(request);
            if (_logger.isDebugEnabled())
                 _logger.debug(SystemConfigUtil.getSetting(SystemConfigUtil.DEFAULT_ENCODING, "UTF-8"));
                _logger.debug("ServletBase.processHttpRequest(" + this.getClass().getName() + ") beginning for user " + (user == null ? "guest" : user.getEmailAddress()) + ".");
                java.util.Enumeration theEnum = request.getParameterNames();
                while (theEnum.hasMoreElements())
                    String name = (String)theEnum.nextElement();
                    String []values = request.getParameterValues(name);
                    if (values.length == 1)
                        _logger.debug("  Parameter " + name + "=" + values[0]);
                    else
                        for (int i=0; i<values.length; i++)
                            _logger.debug("  Parameter " + name + "[" + i + "]=" + values);
The output in the debug log for this looks like:
UTF-8
[2010-06-24 08:45:51,955]:[DEBUG]:[com.towers.core.servlet.ServletBase] - ServletBase.processHttpRequest(com.towers.mafwk.servlet.reporting.JobSearchServlet) beginning for user null.
[2010-06-24 08:45:51,955]:[DEBUG]:[com.towers.core.servlet.ServletBase] - Parameter clientdata=A10168526710
[2010-06-24 08:45:51,955]:[DEBUG]:[com.towers.core.servlet.ServletBase] - Parameter value=?????? *<--------------------------- In Tomcat this shows what looks like a UTF-8 string*
[2010-06-24 08:45:51,965]:[DEBUG]:[com.towers.core.servlet.ServletBase] - About to call subclass processHttpRequest
I cannot figure out why this all works correctly on TomCat in my Windows XP environment but fails on the Weblogic environment in Windows Server 2003

Answer 1

Some more information:
Weblogic version 9.2
When receiving the message in the servlet, the parameter in the URL is translated using the code:
new String(myParam.getBytes("8859_1"),"UTF8")
The output of this is showing as ???? in the weblogic logs and as correct cyrillic strings in the Tomcat console.