Java Articles - Page 288 of 745

A JList is a component that can extend JComponent class used to display a list of objects that allows the user to select one or more items.There are three types of selection modes for a JList in JavaListSelectionModel.SINGLE_SELECTION: Only one list index can be selected at a time.ListSelectionModel.SINGLE_INTERVAL_SELECTION: Only one contiguous interval can be selected at a time.ListSelectionModel.MULTIPLE_INTERVAL_SELECTION: In this mode, there is no restriction on what can be selected. This is a default mode.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class JListSelectionModeTest extends JFrame implements ActionListener {    private JList list;    private DefaultListModel listModel;    public JListSelectionModeTest() {     ... Read More

The program uses a JLabel to hold a count label, a JTextField component to hold the number count, JButton component to create add, remove and reset buttons. When we click the add button, the count in the JTextField will get incremented by '1' and by clicking the remove button the count will be decremented by '1'. If we click the Reset button, it will reset the count to '0'.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class CounterTest extends JFrame implements ActionListener {    private JLabel label;    private JTextField text;    private JButton addBtn, removeBtn, resetBtn;    private int count;    public CounterTest() {       setTitle("Counter Test");   ... Read More

In this article, we will learn to set a border for JCheckBox in Java. JCheckBox is a Swing component that is commonly used in user interface selection. Although it includes a default appearance, we can customize its look by setting borders in order to have a good visual effect. What is a JCheckBox? A JCheckBox is a component that extends JToggleButton, and an object of JCheckBox represents an option that can be checked or unchecked. Syntax The following is the syntax for JCheckBox initialization: JCheckBox Checkbox_name = new JCheckBox(); If there are two or more options, then any ... Read More

A JTextField is a child class of the JTextComponent class through which a single line of text can be edited. Cut, copy, and paste operations of the JTextField component can be implemented using the cut(), copy(), and paste() methods. These are built-in methods in the JTextField class. built-in methodsJTextField class The Cut Operation Cutting involves removing selected text from the JTextField and placing it on the clipboard. Method Declaration: public void cut() { textField.cut(); } The Copy Operation Copying places a copy of the selected text on the clipboard without removing it from the JTextField. Method ... Read More

In Java, a JTextField can be used for plain text, whereas a JFormattedTextField is a class that extends JTextField, and it can be used to set any format to the text that it contains, phone numbers, e-mails, dates, etc. JTextField A JTextField is one of the most important components that allows the user to type an input text value in a single-line format. A JTextField can also generate the MouseListener and KeyListener interfaces. Syntax The following is the syntax for a JTextField initialization: JTextField textField = new JTextField(20); // 20 columns wide A JTextField can generate an ActionListener interface ... Read More

The Arrays class of the java.util package provides a method named toString() this method accepts an array value (of any type) and returns a String.ExampleFollowing Java program accepts various arrays from the user, converts them into String values and prints the results. Live Demoimport java.util.Arrays; import java.util.Scanner; public class ObjectArrayToStringArray {    public static void main(String args[]){       Scanner sc = new Scanner(System.in);       //Integer array to String       System.out.println("Enter 5 integer values: ");       int intArray[] = new int[5];       for(int i=0; i

An interface in Java is similar to class but, it contains only abstract methods and fields which are final and static.Just like classes you can extend one interface from another using the extends keyword as shown below −interface ArithmeticCalculations{    public abstract int addition(int a, int b);    public abstract int subtraction(int a, int b); } interface MathCalculations extends ArithmeticCalculations{    public abstract double squareRoot(int a);    public abstract double powerOf(int a, int b); }But, when you implement the sub-class you need to provide body for the abstract methods in both interfaces.ExampleIn the following example we have created two interfaces ... Read More

In this article, we will learn to implement a JLabel text with different colors and fonts in Java. JLabel is commonly used for simple text display, it can be enhanced to show text with multiple colors and fonts. JLabel A JLabel class can extend the JComponent class, and an object of JLabel provides text instructions or information on a GUI. A JLabel can display a single line of read-only text, an image, or both text and an image. A JLabel can explicitly generate a PropertyChangeListener interface. Different Approaches The following are the two different approaches to implementing a JLabel text ... Read More

In this article, we will learn to insert multiple tabs into a single JTabbedPane in Java. The Java Swing's JTabbedPane enables you to group content into several tabs in one container. JTabbedPane A JTabbedPane is a component can extends the JComponent class, and we can able to see only one tab at a time. Each tab is associated with a single component that can be displayed when the tab is selected. Syntax Object declaration and instantiation using the Java class JTabbedPane: JTabbedPane tabbedPane = new JTabbedPane(); A JTabbedPane can generate a ChangeListener interface when a tab is ... Read More

In this article, we will learn to draw a rounded rectangle using the Graphics object in Java. Drawing shapes is a basic feature of Java 2D graphics programming. Though the Graphics class offers methods for drawing common rectangles, drawing rounded rectangles involves some special techniques. Graphics Class In Java, the drawing takes place via a Graphics object, which is an instance of the java.awt.Graphics class. Each Graphics object has its own coordinate system, and all the methods of Graphics, including those for drawing Strings, lines, rectangles, circles, polygons, etc. We can get access to the Graphics object through the paint(Graphics ... Read More