java - 错误“线程“AWT-EventQueue-0”中的异常 java.lang.NumberFormatException：对于输入字符串：“”” java Netbeans

Question

我正在做一个带有polimorfism之类的练习程序，我有错误“线程中的异常“AWT-EventQueue-0”java.lang.NumberFormatException：对于输入字符串：“””这是代码

package functions;

import javax.swing.JOptionPane;

/**
 *
 * @author angel
 */
public class Sumas extends interface.Sum {
 interface.Sum sum = new interface.Sum();
    public void Sum() {
       
         int num1 = Integer.parseInt(sum.jTextField1.getText());
        int num2 = Integer.parseInt(sum.jTextField2.getText());
        int r= num1 + num2;
        
        JOptionPane.showMessageDialog(null, "The result is : " + r);
    }
}

请帮忙

标签： javaswingparsingnetbeansjoptionpane