code: public static void expandAll(JTree tree)
      {
          int r = 0;
          while (r < tree.getRowCount())
          {
              tree.expandRow(r);
              r++;
          }
      }
docs: Expand all rows of the given tree. <br>
  <br>
  Note that for large trees, {@link #expandAllFixedHeight(JTree)} may
  be significantly faster.
  
  @param tree The tree