code: private boolean builtInEdit(String initialText,
              Consumer<String> saveHandler, Consumer<String> errorHandler) {
          try {
              ServiceLoader<BuildInEditorProvider> sl
                      = ServiceLoader.load(BuildInEditorProvider.class);
              // Find the highest ranking provider
              BuildInEditorProvider provider = null;
              for (BuildInEditorProvider p : sl) {
                  if (provider == null || p.rank() > provider.rank()) {
                      provider = p;
                  }
              }
              if (provider != null) {
                  provider.edit(getResourceString("jshell.label.editpad"),
                          initialText, saveHandler, errorHandler);
                  return true;
              } else {
                  errormsg("jshell.err.no.builtin.editor");
              }
          } catch (RuntimeException ex) {
              errormsg("jshell.err.cant.launch.editor", ex);
          }
          fluffmsg("jshell.msg.try.set.editor");
          return false;
      }
docs: start the built-in editor