线程异常 "JavaFX Application Thread" java.lang.NoClassDefFoundError

Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError

我卡住了,无法自拔。
我的项目结构如下所示:


QuizMaker 中,我想创建一个 Quiz_GUI javafx class 的新实例,出于测试目的,我想在其中开始一个测验。但是,当我编译所有内容时出现错误:

Exception in thread "JavaFX Application Thread" java.lang.NoClassDefFoundError: InvalidQuizFormatException at QuizMaker.lambda$start[=17=](QuizMaker.java:35)

import javafx.scene.layout.Pane;


public class Quiz_GUI extends Pane {
    private String fileName;


   public Quiz_GUI(String fileName) {
        this.fileName = fileName;
        startQuiz();
   }


   private void startQuiz() {

        try {
            Quiz newQuiz;
            newQuiz = Quiz.loadFromFile(this.fileName);
            newQuiz.start();
        } catch (InvalidQuizFormatException e) {
            System.out.println(e);
        }

    }
}

QuizMaker 我有:

Quiz_GUI myQuiz = new Quiz_GUI(fileName);

InvalidQuizFormatException 替换为 Exception,它将起作用,因为这是默认例外 class。