The cell width and height of a JList can be defined by setting the fixedCellWidth and fixedCellHeight properties. These properties have a corresponding methods called setFixedCellWidth(int width) and setFixedCellHeight(int height).

package org.kodejava.swing;

import javax.swing.*;
import java.awt.*;
import java.util.Vector;

public class JListCellWidthAndHeight extends JFrame {
    public JListCellWidthAndHeight() {
        initialize();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new JListCellWidthAndHeight().setVisible(true));
    }

    private void initialize() {
        // Initialize windows default close operation, size and the layout
        // for laying the components.
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(500, 175);
        setLayout(new BorderLayout(5, 5));

        // Create a list of vector data to be used by the JList component.
        Vector<String> v = new Vector<>();
        v.add("A");
        v.add("B");
        v.add("C");
        v.add("D");

        JList<String> list = new JList<>(v);
        list.setFixedCellWidth(50);
        list.setFixedCellHeight(50);

        JScrollPane pane = new JScrollPane(list);

        // Add an action listener to the button to exit the application.
        JButton button = new JButton("CLOSE");
        button.addActionListener(e -> System.exit(0));

        // Add the scroll pane where the JList component is wrapped and
        // the button to the center and south of the panel
        getContentPane().add(pane, BorderLayout.CENTER);
        getContentPane().add(button, BorderLayout.SOUTH);
    }
}

JList Cell Width and Height Demo

JList is a component that displays a list of objects and allow user to select one or more items. To create an instance of JList we can pass a vector, an array of objects or a ListModel. In this example we will pass an array of objects that contains a date, string and numbers as the parameters.

By default, the list does not display a scrollbar. To give our JList component a scrollbar we must wrap it with a JScrollPane.

package org.kodejava.swing;

import javax.swing.*;
import java.awt.*;
import java.util.Date;

public class CreateJListDemo extends JFrame {

    public CreateJListDemo() {
        initialize();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(
                () -> new CreateJListDemo().setVisible(true));
    }

    // Initialize the components and configuration of our CreateJListDemo.
    private void initialize() {
        // Define the window title, size and the default close operation.
        this.setTitle("Create JList Demo");
        this.setSize(500, 175);
        this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        // Create an array of arbitrary objects for the JList to display.
        Object[] data = new Object[]{
                new Date(), "One", 1, Long.valueOf("12345"), "Four", "Five"
        };

        // Create an instance of JList and pass data variable as the
        // initial content of it. By default, the JList does not have a
        // scrolling behaviour, so we create a JScrollPane as the container
        // for the JList.
        JList<Object> list = new JList<>(data);
        JScrollPane scrollPane = new JScrollPane(list);

        // Add a button to close the program.
        JButton button = new JButton("Close");
        button.addActionListener(e -> System.exit(0));

        // Set the panel layout to BorderLayout and place the list in the
        // center and the button on the south.
        this.setLayout(new BorderLayout(5, 5));
        getContentPane().add(scrollPane, BorderLayout.CENTER);
        getContentPane().add(button, BorderLayout.SOUTH);
    }
}

Swing JList Demo