WindowListener是接口吗？但是根据以下情况，实例化如何有效？我们不能实例化接口吧？
WindowListener l1=new WindowListener() {
public void windowOpened(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowIconified(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowDeiconified(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowDeactivated(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowClosing(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowClosed(WindowEvent e) {
// TODO Auto-generated method stub
}
public void windowActivated(WindowEvent e) {
// TODO Auto-generated method stub
}
};