code: private void installPrePackagedUIManagerDefaults() {
          try {
              UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
              UIManager.put("Tree.line", "Angled");
              UIManager.put("Tree.leafIcon", null);
              UIManager.put("Tree.closedIcon", null);
              UIManager.put("Tree.openIcon", null);
              UIManager.put("Tree.rightChildIndent", new Integer(10));
          } catch (Exception e) {
              throw new ApplicationException("Unable to set defaults", e);
          }
      }
docs: Initializes the UIManager defaults to values based on recommended,
  best-practices user interface design. This should generally be called
  once by an initializing application class.