在Java中绘制圆

import javax.swing.*;
import java.awt.*;

public class DrawCircle extends JFrame {
    public DrawCircle() {
        setTitle("Draw Circle");
        setSize(400, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setVisible(true);
    }

    public void paint(Graphics g) {
        super.paint(g);
        Graphics2D g2d = (Graphics2D) g;
        g2d.setColor(Color.RED);
        g2d.drawOval(100, 100, 200, 200);
    }

    public static void main(String[] args) {
        new DrawCircle();
    }
}