code: public static String getTreeImageLocation()
      {
          if (defaultTreeImageLocation == null) {
              JspTagConfig tagConfig = ConfigUtil.getConfig().getJspTagConfig();
              if (tagConfig != null) {
                  String s = tagConfig.getTreeImageLocation();
                  defaultTreeImageLocation = (s != null) ? s : InheritableState.DEFAULT_IMAGES;
              }
              else
                  defaultTreeImageLocation = InheritableState.DEFAULT_IMAGES;
          }
          assert(defaultTreeImageLocation != null);
          return defaultTreeImageLocation;
      }
docs: This method returns the default location for the tree images.  This may be configured by setting
  the &lt;tree-image-location> element in the netui.config file to the location of the images.
  This location should not include the context path of the webapp or the leading '/', but should be an absolute
  path within the webapp.
  <p>&lt;tree-image-location>resources/images&lt;/tree-image-location>
  </p>
  @return the default location of the tree images.