含if判断的for循环后出现Unreachable Statement不可达语句报错排查

我有一个非常基础的作业，但对我而言仍是全新的领域。程序要求询问用户输入姓名、姓氏、年级和科目：如果输入的科目不是IT，就忽略该条输入；如果输入的科目是IT，后续会复用用户的姓名、姓氏和年级信息，按要求格式展示随输入内容动态变化的消息。
我遇到的问题是：我编写的代码逻辑正确，但末尾使用JOptionPane展示消息的代码行报错Unreachable Statement（不可达语句）。十分奇怪的是，这段代码和作业的参考答案几乎完全一致，却仍出现报错。我猜测可能是Netbeans的识别问题，我在家重写的代码可以正常运行，代码如下：

String name, surname, subject, message = "IT Learners:\n\n";
int grade, counter = 0;

for (int i = 0; i < 3; i++) {
    name = JOptionPane.showInputDialog("Enter Your Name Here: ");
    surname = JOptionPane.showInputDialog("Enter Your Surname Here: ");
    subject = JOptionPane.showInputDialog("Enter Your Subject Here: ");
    grade = Integer.parseInt(JOptionPane.showInputDialog("Enter Your "
            + "Grade Here: "));

    if (subject.equalsIgnoreCase("IT")) {
        message += name + " " + surname + " is in grade "
                + grade + ".\n";
        counter++;
    }
}
JOptionPane.showMessageDialog(null, message + "There is a total of "
        + counter + " IT Learners.");

下方是我在学校上课时编写的代码，我个人看不出两处代码的区别，因此想咨询这段代码是否正确，或是我漏看了什么不易察觉的小错误？
我在学校编写的代码：

String name, surname, subject, message = "IT Learners:\n\n";
int grade, counter = 0;

for (int i = 0; i < 3; i++) {
    name = JOptionPane.showInputDialog("Enter Your Name Here: ");
    surname = JOptionPane.showInputDialog("Enter Your Surname Here: ");
    subject = JOptionPane.showInputDialog("Enter Your Subject Here: ");
    grade = Integer.parseInt(JOptionPane.showInputDialog
            ("Enter Your Grade Here: "));

    if (subject.equalsIgnoreCase("IT")) 
    {
        message += name + " " + surname + " is in grade "
                + grade + ".\n";
        counter++;
    }
}
JOptionPane.showMessageDialog(null, message + "There is a total of "
        + counter + " IT Learners.");

两份代码看起来完全一致，请问该报错是Netbeans自身识别混乱导致的，还是我确实漏看了什么细节？
完整代码如下：

import javax.swing.JOptionPane;

/**
*
* @author (My Name)
*/
public class ITLearners {

public static void main(String[] args) {
// TODO code application logic here
String name, surname, subject, message = "IT Learners:\n\n";
int grade, counter = 0;

for (int i = 0; i < 3; i++) {
    name = JOptionPane.showInputDialog("Enter Your Name Here: ");
    surname = JOptionPane.showInputDialog("Enter Your Surname Here: ");
    subject = JOptionPane.showInputDialog("Enter Your Subject Here: ");
    grade = Integer.parseInt(JOptionPane.showInputDialog("Enter Your "
            + "Grade Here: "));

    if (subject.equalsIgnoreCase("IT")) {
        message += name + " " + surname + " " + " is in grade "
                + grade + ".\n";
        counter++;
    }
}
JOptionPane.showMessageDialog(null, message + "There is a total of "
        + counter + " IT Learners.");
}
}

问题原因及解决方案 #

你贴出的所有代码本身语法、逻辑完全正确，不存在会触发不可达语句报错的问题，该报错可按以下优先级排查：

• 优先考虑是NetBeans IDE缓存异常导致：点击顶部菜单栏文件 -> 选择清理并构建项目，等待构建完成后重新运行代码即可解决绝大多数缓存类异常
• 如果清理项目缓存后问题仍存在，删除NetBeans全局缓存：关闭NetBeans，找到对应系统的缓存目录（Windows一般为C:\Users\你的用户名\.netbeans\版本号\var\cache，macOS为~/Library/Caches/NetBeans/版本号），删除整个cache目录后重启IDE即可
• 额外校验：确认学校版本的实际代码中，for循环体末尾没有误加return、System.exit()这类会提前终止main方法执行的语句，你贴出的代码里没有这类逻辑，但如果实际编写时不小心添加了，就会导致后续JOptionPane代码永远无法执行，触发不可达语句报错

内容的提问来源于stack exchange，提问作者RandomCoder