如果我不断收到错误怎么办：在封闭作用域中定义的局部变量 j 必须是最终的或有效的最终

Question

i am trying to read how many rows are there on the location (i) and display separated by enter which one is displayed at the moment(j) - example 1 of 15 when pressed enter will display 2 of 15 here's part of code which causes error:

int i = 0;
        int j = 0;


        try {
            ResultSet rs = stmt.executeQuery("SELECT * FROM product WHERE Location = 'REC1U'");
            while(rs.next()) {
                i++;
            }
            rs.next();
            tfield.addKeyListener(new KeyAdapter() {
                @Override
                public void keyPressed(KeyEvent e) {
                    if(e.getKeyCode() == KeyEvent.VK_ENTER) {
                        j++; // <--- this is causing above error
                        String l = String.valueOf(j);

                        count.setText(l);
                    }
                }

                });
        } finally {
            stmt.close();
        }

i have tried to make it final just to try to get rid of it but it wouldn't work anyways...

Answer 1

You can use an object that has a counter inside which is final. For example:

final AtomicInteger j = new AtomicInteger(0);

//...
public void keyPressed(KeyEvent e) {
    j.incrementAndGet();
}