调用TreeSelectionListener接口后报错,请指点()

调用TreeSelectionListener接口后报错,请指点(在线等)
代码如下:
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import   java.awt.*;
import   java.awt.event.*;
import   javax.swing.*;
import   javax.swing.event.*;
import   javax.swing.tree.*;


public   class   EventFrame   extends   JFrame   implements   TreeSelectionListener{
    JPanel   contentPane;
    JSplitPane   jSplitPane1   =   new   JSplitPane();
    JTree   jTree1   =   new   JTree();
………………
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现在报错如下：
"EventFrame.java ":   moneymanager.EventFrame   should   be   declared   abstract;   it   does   not   define   valueChanged(javax.swing.event.TreeSelectionEvent)   in   moneymanager.EventFrame   at   line   19,   column   1。   19行就是上面public   class……   那一行。请指点一下。谢谢

------解决方案--------------------
你要实现valueChanged
这个方法。