朋友们帮一下一下java的问题

设计一个描述电脑信息的类，包含4个属性有：型号、颜色、屏幕尺寸、硬
盘容量，2个构造方法：有参构造和无参构造，2个成员方法：开机、听音乐

package Account_system;

class ComputerInfo{
    private String type;
    private String color;
    private    double screenSize;
    private double diskSize;
    
    protected ComputerInfo() {
        super();
    }

    protected ComputerInfo(String type, String color, double screenSize, double diskSize) {
        super();
        this.type = type;
        this.color = color;
        this.screenSize = screenSize;
        this.diskSize = diskSize;
    }
    
    public void startUp() {
        System.out.println("开机。。。");
    }
    public void listenMiusc() {
        System.out.println("听歌...");
    }
    public void shutDown() {
        System.out.println("关机。。。");
    }
}

public class Answer7733791 {

    public static void main(String[] args) {
        ComputerInfo pc = new ComputerInfo();
        pc.startUp();
    }

}