code: public void setContentLength(int len) {
          if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE)) {  //306998.15
              logger.entering(CLASS_NAME,"setContentLength", "length --> " + String.valueOf(len) + " ["+this+"]");
          }
  
          // d151464 - check the include flag
          WebAppDispatcherContext dispatchContext = (WebAppDispatcherContext) getRequest().getWebAppDispatcherContext();
          if (dispatchContext.isInclude() == true) {
              if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE)) {  //306998.15
                  logger.logp(Level.FINE, CLASS_NAME,"setContentLength", nls.getString("Illegal.from.included.servlet", "Illegal from included servlet"), "setContentLength length --> " + String.valueOf(len));  //311717
              }
          }
          else
          {
              if (_response!=null) {
                  if (!_response.isCommitted()) {
                      _response.setContentLength(len);
                  }
              }
              _contentLength = len;
              // LIBERTY _bufferedOut.setLimit(_contentLength = len);
              _bufferedWriter.setLimitLong(_contentLength);
              //still want to try to set the header even if the response is committed to throw the warning
              setIntHeader(HEADER_CONTENT_LENGTH, len);
          }
          if (com.ibm.ejs.ras.TraceComponent.isAnyTracingEnabled()&&logger.isLoggable (Level.FINE)) {  //306998.15
              logger.exiting(CLASS_NAME,"setContentLength");
          }
      }
docs: Defines the content length for this response.  This call must be made only once.
  Not setting the content length may cause significant performance degradation.
  
  @param len The content length.