关于调用继承runnable接口后类的方法

[zz60708320]

这是部分代码
import java.awt.event.*;
import javax.swing.*;

class Ticke implements Runnable
{
private int i;

public void getnum(int i)
{
this.i=i;
}

public int outputnum()
{
return i;
}

public void run()
{
i--;
}
}


public class ComputerListener implements ActionListener
{
JTextArea textshow;
String luxian;

public void setJTextArea(JTextArea area)
{
textshow=area;
}

public void setLuxian(String s)
{
luxian=s;
}
public void actionPerformed(ActionEvent e)
{
try
{
int i=40;
textshow.setText("");
if(luxian.equals("和平->广州"))
{
Ticke t=new Ticke();
t.getnum(i);
到这里，t.getnum(i);运行时会出现
exception in thread Awt-EventQueue-0 java.long.NotSuchMethodError:Ticke.getnum的错误。怎么回事啊？？