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我正在尝试从 Java 应用程序在 Oracle 数据库中并行进行多个读取查询。我使用 CallableTasks 进行这些查询。Callable Task的样例如下：

public class MyCallableTask<T> implements Callable<List<T>> {
    
    private String sql;
    private Connection connection;
    private Class<T> classInstance;

    public MyCallableTask(String sql, Connection connection, Class<T> classInstance) {
//      the connection object is sent here from a db connection pool, so that each callable has its own connection instance.
        this.connection = connection;
        this.sql = sql;
        this.classInstance = classInstance;
    }

    @Override
    public List<T> call() throws Exception {
        PreparedStatement ps = connection.createPreparedStatement(sql);
        Resultset rs = ps.executeQuery();
//      Using commons-dbutils resultsethandler to map the resultset to a Java Bean
        ResultSetHandler<List<T>> resultSetHandler = new BeanListHandler<>(classInstance);
        List<T> requiredList = resultSetHandler.handle(rs);
        return requiredList;
    }

}

我的示例主类如下所示：

public class MyMain {

    public static void main() {
        MyConnectionPool myConnectionPool = new MyConnectionPool();
        Connection connection1 = myConnectionPool.getConnection();
        Connection connection2 = myConnectionPool.getConnection();
        String studentSql = "Select X, Y from AB.Students Where Z = 2";
        String teacherSql = "Select P, Q from AB.Teachers Where R = 1";
        ExecutorService executorService = Executors.newFixedThreadPool(6);
        Callable<List<Student>> callableStudents = new MyCallableTask<>(studentSql, connection1, Student.class);
        Callable<List<Teacher>> callableTeachers = new MyCallableTask<>(teacherSql, connection2, Teacher.class);
        Future<List<Student>> studentsFuture = executorService.submit(callableStudents);
        Future<List<Teacher>> teachersFuture = executorService.submit(callableTeachers);
        List<Student> students = studentsFuture.get();
        List<Teacher> teachers = teachersFuture.get();
        System.out.println(students + " " + teachers);
    }

}

上面的代码按预期适用于两个不同线程上的每个 sql 查询，但在我调用的行上失败

List<T> requiredList = resultSetHandler.handle(rs);

抛出的异常是 NoSuchElementException。这个案例对我来说很好奇，因为当我同步运行上述内容时，它工作得非常好。事实上，即使我插入断点并在调试模式下运行，它也运行得非常好，并按预期创建了两个不同的工作线程。但它总是在正常运行时中断。

如果可能，请尝试回答。非常感谢任何帮助。

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