code: public void println(String s) throws IOException
      {
          if(this._listener!= null &&  !checkIfCalledFromWLonError()){
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())    
                  Tr.debug(tc, "non blocking println String , WriteListener enabled: " + this._listener);
              if(s!=null){
                  this.println_NonBlocking(s);
              }            
          }
          else {
              if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled())    
                  Tr.debug(tc, "println String");
              super.println(s);
          }
      }
docs: /*
  @see javax.servlet.ServletOutputStream#println(java.lang.String)