How to make an input form in Java code (not Netbeans using JForm)?

You are currently using a GridLayout, which can be fine for your need.

However, you should initialize it with the actual number of rows and columns you will need. In your case:

new GridLayout(0, 2); 

0 for rows means there is not limit, and you have 2 columns, one for the labels, and one for the input component. See the Java tutorial for more information on GridLayouts.

_{(source: sun.com)}

Note however that the GridLayout will make all "cells" to be the same size, which can be a problem for the labels.

However, Jonas is right, a SpringLayout is probably more adapted to your need.

Yes, you have to change layout. Have a look at SpringLayout and this example:

_{(source: sun.com)}

String[] labels = {"Name: ", "Fax: ", "Email: ", "Address: "};
int numPairs = labels.length;

//Create and populate the panel.
JPanel p = new JPanel(new SpringLayout());
for (int i = 0; i < numPairs; i++) {
    JLabel l = new JLabel(labels[i], JLabel.TRAILING);
    p.add(l);
    JTextField textField = new JTextField(10);
    l.setLabelFor(textField);
    p.add(textField);
}

//Lay out the panel.
SpringUtilities.makeCompactGrid(p,
                                numPairs, 2, //rows, cols
                                6, 6,        //initX, initY
                                6, 6);       //xPad, yPad

SpringLayout works fine for this simple form, but there is third party libraries that has more features. I.e. MiG Layout.

Another way to create a form using GridBagLayout, producing the following result:

Code:

JPanel addressPanel = new JPanel();
Border border = addressPanel.getBorder();
Border margin = new EmptyBorder(10, 10, 10, 10);
addressPanel.setBorder(new CompoundBorder(border, margin));

GridBagLayout panelGridBagLayout = new GridBagLayout();
panelGridBagLayout.columnWidths = new int[] { 86, 86, 0 };
panelGridBagLayout.rowHeights = new int[] { 20, 20, 20, 20, 20, 0 };
panelGridBagLayout.columnWeights = new double[] { 0.0, 1.0, Double.MIN_VALUE };
panelGridBagLayout.rowWeights = new double[] { 0.0, 0.0, 0.0, 0.0, 0.0,
                                               Double.MIN_VALUE };
addressPanel.setLayout(panelGridBagLayout);

addLabelAndTextField("City:", 0, addressPanel);
addLabelAndTextField("Street:", 1, addressPanel);
addLabelAndTextField("State:", 2, addressPanel);
addLabelAndTextField("Phone:", 3, addressPanel);
addLabelAndTextField("Mail:", 4, addressPanel);

The helper method addLabelAndTextField:

private void addLabelAndTextField(String labelText, int yPos,
                                  Container containingPanel) {

    JLabel label = new JLabel(labelText);
    GridBagConstraints gridBagConstraintForLabel = new GridBagConstraints();
    gridBagConstraintForLabel.fill = GridBagConstraints.BOTH;
    gridBagConstraintForLabel.insets = new Insets(0, 0, 5, 5);
    gridBagConstraintForLabel.gridx = 0;
    gridBagConstraintForLabel.gridy = yPos;
    containingPanel.add(label, gridBagConstraintForLabel);

    JTextField textField = new JTextField();
    GridBagConstraints gridBagConstraintForTextField = new GridBagConstraints();
    gridBagConstraintForTextField.fill = GridBagConstraints.BOTH;
    gridBagConstraintForTextField.insets = new Insets(0, 0, 5, 0);
    gridBagConstraintForTextField.gridx = 1;
    gridBagConstraintForTextField.gridy = yPos;
    containingPanel.add(textField, gridBagConstraintForTextField);
    textField.setColumns(10);
}