在Java中實現點擊驗證碼通常需要使用GUI庫來創建驗證碼圖像并監聽用戶的點擊事件。以下是一個簡單的示例代碼來實現點擊驗證碼：

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;

public class ClickCaptcha extends JFrame {

    private static final int WIDTH = 200;
    private static final int HEIGHT = 100;

    private int x;
    private int y;

    public ClickCaptcha() {
        setTitle("Click Captcha");
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        x = new Random().nextInt(WIDTH);
        y = new Random().nextInt(HEIGHT);

        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                int clickX = e.getX();
                int clickY = e.getY();

                if (clickX >= x && clickX <= x + 20 && clickY >= y && clickY <= y + 20) {
                    JOptionPane.showMessageDialog(null, "Verification successful!");
                } else {
                    JOptionPane.showMessageDialog(null, "Verification failed!");
                }

                x = new Random().nextInt(WIDTH);
                y = new Random().nextInt(HEIGHT);
                repaint();
            }
        });
    }

    @Override
    public void paint(Graphics g) {
        super.paint(g);

        g.setColor(Color.BLACK);
        g.fillRect(x, y, 20, 20);
    }

    public static void main(String[] args) {
        ClickCaptcha clickCaptcha = new ClickCaptcha();
        clickCaptcha.setVisible(true);
    }
}

在這個示例中，我們創建了一個繼承自JFrame的ClickCaptcha類，窗口大小為200x100。在窗口內部隨機生成一個20x20的黑色方塊作為驗證碼。當用戶點擊窗口時，判斷點擊的位置是否在驗證碼方塊內，如果在則驗證成功，否則驗證失敗，并重新生成新的驗證碼。