类分层结构
- java.lang.Object
- java.awt.Component (implements java.awt.image.ImageObserver, java.awt.MenuContainer, java.io.Serializable)
- java.awt.Container
- javax.swing.JComponent (implements java.io.Serializable)
- javax.swing.JLabel (implements javax.accessibility.Accessible, javax.swing.SwingConstants)
- javax.swing.JPanel (implements javax.accessibility.Accessible)
- javax.swing.tree.DefaultMutableTreeNode (implements java.lang.Cloneable, javax.swing.tree.MutableTreeNode, java.io.Serializable)
- java.awt.event.MouseAdapter (implements java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.awt.event.MouseWheelListener)