Pretty straight forward.
You are missing the class QuizCard:
You are creating an instance in here:
QuizCard card = new QuizCard(question.getText(), answer.getText());
Of course you need to have that class in the project.
public class QuizCard{ String question,answer; public QuizCard(){} public QuizCard(String q,String a){ question=q; answer=a; } public String getQuestion(){return question;} public String getAnswer(){return answer;} }
Result: