FormPanel (Swing)

import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.Border;

public class FormPanel extends JPanel{

    private JLabel nameLabel;
    private JLabel occupationLabel;
    private JTextField nameField;
    private JTextField occupationField;
    private JButton okBtn;

    // Constructor
    FormPanel(){
        Dimension dim = getPreferredSize();
        dim.width = 250;
        setPreferredSize(dim);

        // Initialize
        nameLabel = new JLabel("Name: ");
        occupationLabel = new JLabel("Occupation: ");
        nameField = new JTextField(10);
        occupationField = new JTextField(10);
        okBtn = new JButton("OK");


        // Create borders
        Border innerBorder = BorderFactory.createTitledBorder("Add Person");
        Border outerBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
        setBorder(BorderFactory.createCompoundBorder(outerBorder, innerBorder));

        // Create a GridBagLayout
        setLayout(new GridBagLayout());
        GridBagConstraints gc = new GridBagConstraints();

        // 1. Create title "name" in left (gridx, gridy: like matrix' elements)
        gc.gridx = 0;
        gc.gridy = 0;
        gc.weightx = 1;
        gc.weighty = 1;
        gc.fill = GridBagConstraints.NONE;
        gc.anchor = GridBagConstraints.LINE_END;
        add(nameLabel, gc);

        // 2. Create a field (right to the "name") to write on
        gc.gridx = 1;
        gc.gridy = 0;
        gc.anchor = GridBagConstraints.LINE_START;
        add(nameField, gc);

        // 3. Create a title "occupation" in left and under the "name"
        gc.gridx = 0;
        gc.gridy = 1;
        gc.anchor = GridBagConstraints.LINE_END;
        add(occupationLabel, gc);

        // 4. Create a field (under the "nameField" and right to the "occupation") as the 4th element of my matrix
        gc.gridx = 1;
        gc.gridy = 1;
        gc.anchor = GridBagConstraints.LINE_START;
        add(occupationField, gc);

        // 5. Add the okBtn
        gc.gridy = 2;               // Katevainw ston y 2 theseis
        gc.gridx = 1;
        gc.anchor = GridBagConstraints.LINE_START;// Proxwraw ston x 1 thesi
        add(okBtn, gc);

    }
}