src/share/classes/javax/swing/plaf/nimbus/TableScrollPaneCorner.java

@@ -46,11 +46,12 @@
 
     /**
      * Paint the component using the Nimbus Table Header Background Painter
      */
     @Override protected void paintComponent(Graphics g) {
-        Painter painter = (Painter) UIManager.get(
+        @SuppressWarnings("unchecked")
+        Painter<JComponent> painter = (Painter) UIManager.get(
             "TableHeader:\"TableHeader.renderer\"[Enabled].backgroundPainter");
         if (painter != null){
             if (g instanceof Graphics2D){
                 painter.paint((Graphics2D)g,this,getWidth()+1,getHeight());
             } else {