code: public static String getTreeRendererClassName()
      {
          if (defaultTreeRendererClassName == null) {
              JspTagConfig tagConfig = ConfigUtil.getConfig().getJspTagConfig();
              if (tagConfig != null) {
                  // the schema config includes a default value so we shouldn't
                  // get a null value from the config object.
                  defaultTreeRendererClassName = tagConfig.getTreeRendererClass();
              }
          }
          return defaultTreeRendererClassName;
      }
docs: This method returns the class name of the renderer to use for NetUI
  trees in the Web application. The class name returned will usually
  be the predefined default NetUI implementation,
  {@link org.apache.beehive.netui.tags.tree.TreeRenderer}, unless
  NetUI is configured to use a different implementation.
  This may be configured by setting the &lt;tree-renderer-class>
  element in the beehive-netui-config file to the name of a class that
  extends {@link org.apache.beehive.netui.tags.tree.TreeRenderer}.
  <p>&lt;tree-renderer-class>com.xyz.tree.CustomTreeRenderer&lt;/tree-renderer-class>
  </p>
  <p>Note that the NetUI {@link org.apache.beehive.netui.tags.tree.Tree}
  tag has an attribute for setting the name of the TreeRenderer class to
  use on a tree by tree bases.
  </p>
  @return the name of the class to use to renderer the trees in the application.