code: @Override
      public ServletOutputStream getOutputStream() throws IOException {
          if (TraceComponent.isAnyTracingEnabled() && tc.isDebugEnabled()) {
              Tr.debug(tc, "getOutputStream: " + this);
          }
          if (null != this.outWriter) {
              throw new IllegalStateException("Output writer already obtained");
          }
          this.streamActive = true;
          return this.outStream;
      }
docs: /*
  @see javax.servlet.ServletResponse#getOutputStream()