returning a value to main after clicking JButton but the JFrame disappears

Question

New to java and new to GUI, so my code might not be perfect, but I'm trying to get the user to input a password. If it's correct, I want to return value 1 to main, and if it isn't, then a value 0 to main.

But this part of the code, although it WORKS, the frame automatically disappears and the control goes back to main returning default value of accessFlag = 0, and the program continues from there.

I want it to wait for user input, instead of appearing and vanishing.

public int access(){

    JFrame frame=new JFrame("LOGIN");


    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    frame.setSize(510,100);
    JPanel panel=new JPanel(new MigLayout("", "[][][]", "[]"));
    frame.add(panel);
    JButton button=new JButton("Enter");
    JLabel label=new JLabel("Enter Password");
    JPasswordField pass=new JPasswordField(10);
    pass.setEchoChar('*');
    panel.add(label,"cell 0 0 1 1");
    panel.add(pass,"cell 1 0 1 1");
    panel.add(button,"cell 2 0 1 1");
    frame.setVisible(true);

    button.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            JPasswordField input=(JPasswordField) e.getSource();
            char[] passwordArray= input.getPassword();
            String passwordString= new String(passwordArray);

            if(passwordString.equals(password)){
                JOptionPane.showMessageDialog(null, "Correct!");
                accessFlag=1;
            }
            else{
                String notAllowed="Incorrect";
                JOptionPane.showMessageDialog(null, notAllowed);
                accessFlag=0;
            }
        }
    });

    return accessFlag;
}