JLayer component and LayerUI class were integrated to JDK 7 with help of RFE #6822696,
however LayerUI class has pretty limited number of methods comparing with its counterpart AbstractLayerUI from the jxlayer.dev.java.net project

To make this class more useful and consisten the following methods should be added,

// Similar to JComponent.paintComponent()
protected void paintLayer(Graphics2D g2, JXLayer<? extends V> l)

// A hook method for configuring graphics instance
protected void configureGraphics(Graphics2D g2, JXLayer<? extends V> l)

// Standart way to repaint the layers
protected void repaintLayer();

// Convenience methods, similar to java.awt.Component
protected void processFocusEvent(FocusEvent);
protected void processMouseEvent(MouseEvent);
protected void processMouseMotionEvent(MouseEvent);
protected void processMouseWheelEvent(MouseWheelEvent);
protected void processKeyEvent(KeyEvent);
protected void processComponentEvent(ComponentEvent);
protected void processInputMethodEvent(InputMethodEvent);
protected void processHierarchyEvent(HierarchyEvent);
protected void processHierarchyBoundsEvent(HierarchyEvent);