堆地址是由堆地址共享的吗？(Is stack address shared by Heap addresses?)

 在每个actionPerformed调用期间，您将遍历整个列表。 这里： 
 
    while(x < questions.length){
        problem.setText(questions[x]);
        response[y] = String.format("%s",event.getActionCommand());
        input.setText("Answer goes here");
        x++;
        y++;
   }
 
 因此，当文本实际再次显示时，您已将其设置为每个不同的问题，但是停止使用最后一个问题，这就是用户实际看到的内容。 每次执行操作时，您只想将文本更改为下一个问题。 
 
 您需要保留某种计数器，以便您可以通过actionPerformed方法访问您所处的问题 
 
 另外，如评论中所述，您需要更改结果检查以使用equals方法。 使用==符号无法比较字符串，因为对于Strings ==比较每个String对象指向的引用，而不是String对象的值 
 
 if(response[z].equals(answers[z]))
     result++;

During each actionPerformed call you cycle through the whole list. Here:
 
    while(x < questions.length){
        problem.setText(questions[x]);
        response[y] = String.format("%s",event.getActionCommand());
        input.setText("Answer goes here");
        x++;
        y++;
   }
 
So by the time the text is actually displayed again, you have set to it to each different question, but stop with the last one and that is what the user actually sees. You only want to change the text once, to the next question, everytime an action is performed.
 
You'll need to keep some sort of counter for which question you are on that can be accessed by the actionPerformed method
 
Also, as mentioned in the comments, you will want to change your result checking to use the equals method. Strings can't be compared using the == sign because for Strings == compares the reference each String object is pointing to, not the value of the String object
 
 if(response[z].equals(answers[z]))
     result++;