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.text.JTextComponent (implements javax.accessibility.Accessible, javax.swing.Scrollable)