one.clj

(defn prepare-renderer [this list item _ selected _]
  (.setOpaque this true)
  (let [[bg fg] (if selected
                  [#(.getSelectionBackground %)
                   #(.getSelectionForeground %)]
                  [#(.getBackground %)
                   #(.getForeground %)])]
    (.setBackground this (bg list))
    (.setForeground this (fg list)))
  (let [[item-type display-string _ _ _] item]
    (.setIcon this (-> item-type item-type-names icons))
    (.setFont this monospace-font)
    (.setText this display-string))
  this)

(def list-cell-renderer
  (doto (-> (get-proxy-class JLabel ListCellRenderer)
            (construct-proxy))
    (init-proxy {"getListCellRendererComponent" prepare-renderer})))

two.clj

(def list-cell-renderer
  (proxy [JLabel ListCellRenderer] []
    (getListCellRendererComponent [list item _ selected _]
      (.setOpaque this true)
      (let [[bg fg] (if selected
                      [#(.getSelectionBackground %)
                       #(.getSelectionForeground %)]
                      [#(.getBackground %)
                       #(.getForeground %)])]
        (.setBackground this (bg list))
        (.setForeground this (fg list)))
      (let [[item-type display-string _ _ _] item]
        (.setIcon this (-> item-type item-type-names icons))
        (.setFont this monospace-font)
        (.setText this display-string))
      this)))