package org.yashwanth.gui;
import java.awt.Dimension;
// Dimension is an Object that helps to store heights and widths
import java.awt.Toolkit;
// Toolkit asks different question of the OS
import javax.swing.*;


public class framing extends JFrame{

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

    }
    public framing(){
        this.setSize(400,400);
        this.setVisible(true);
    }

}

错误：在类org.yashwanth.gui.framing中找不到主方法，请将main方法定义为：public static void main（String [] args）或JavaFX应用程序类必须扩展javafx.application.Application

java swing