Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
Articles by raja
379 articles
What is a Type-safe Enum in Java?
In Java, an enum is a special class that represents a "group of constants" that cannot be changed, just like a "final variables". Java provides an enum keyword to create an enum, and inside the class, the constants are written in uppercase letters and separated by commas (, ). Syntax to create an enum in Java: enum EnumName { CONST1, CONST2, CONST3 // ... } Here, enum: A predefined keyword used to define an enum. EnumName: The name ...
Read MoreWhat are the differences between GridLayout and GridBagLayout in Java?
In Java, a GridLayout puts all the components in a rectangular grid and is divided into equal-sized rectangles, and each component is placed inside a rectangle whereas GridBagLayout is a flexible layout manager that aligns the components vertically and horizontally without requiring that the components be of the same size. Java GridLayout A GridLayout arranges the components in a rectangular grid. It arranges components in the cells, and each cell has the same size. Components are placed in columns and rows. GridLayout(int rows, int columns) takes two parameters that are a column and a row. Syntax The following is the ...
Read MoreHow to create a custom unchecked exception in Java?
In Java, the exceptions are of two types: checked and unchecked exceptions. A checked exception is an exception that occurs at compile time; these are also called compile-time exceptions. An unchecked exception occurs at the time of execution. These are also called Runtime Exceptions. In this article, we will learn to create a custom unchecked exception in Java. We can create a custom unchecked exception by extending the RuntimeException class in Java. What are unchecked exceptions? The unchecked exceptions inherit from the Error class or the RuntimeException class. Many programmers feel that we cannot handle these exceptions in our programs because they represent the type of errors ...
Read MoreHow can we implement a JLabel text with different color and font in Java?
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 MoreHow to change each column width of a JTable in Java?
In this article, we will learn to change each column width of a JTable in Java. JTable is Swing's strongest component for displaying and editing tabular information. Adjusting column widths appropriately to display content is among the most prevalent needs for customization. JTable A JTable is a subclass of JComponent for displaying complex data structures. A JTable can follow the Model View Controller (MVC) design pattern for displaying the data in rows and columns. The DefaultTableModel class can extend AbstractTableModel and it can be used to add the rows and columns to a JTable dynamically. Syntax The following is ...
Read MoreWhat are the differences between a Font and a FontMetrics in Java?\\n
The Font class in Java is responsible for setting screen fonts, which are mapped to characters of the language in specific regions. But a FontMetrics class is said to be a font metrics object that encapsulates the data about the rendering of a specific font on a particular screen. Font A Font class can be used to create an instance of a Font object to set the font for drawing text, labels, text fields, buttons, etc, and it can be specified by its name, style, and size. Syntax The following is the syntax for Font initialization: Font font = new ...
Read MoreHow to center align the items of a JComboBox in Java?
In this article, we will learn to center-align the items of a JComboBox in Java. The default rendering of a JComboBox uses a JLabel for each item. JLabel's default alignment is left-justified, hence the misalignment. JComboBox A JComboBox is a subclass of the JComponent class, and it is a combination of a text field and a drop-down list from which the user can choose a value. A JComboBox can generate an ActionListener, ChangeListener, and an ItemListener when the user actions with a combo box. Center-Align the Items of a JComboBox By default, items in the JCombobox are left-aligned. We ...
Read MoreHow can we display the line numbers inside a JTextArea in Java?
In this article, we will learn to display the line numbers inside a JTextArea in Java. When using text editors or code viewers in Java Swing applications, the showing of line numbers can greatly improve the user experience. What is a JTextArea? A JTextArea is a subclass of JTextComponent and it is a multi-line text component to display the text or allow the user to enter a text. A JTextArea can generate a CaretListener interface, which can listen to caret update events. Syntax The following is the syntax for JTextArea initialization: JTextArea textArea = new JTextArea(); By default, JTextArea does ...
Read MoreHow to save the elements of a TreeSet to a file in Java?
A TreeSet is a subclass of AbstractSet class and it does not allow duplicate elements. By default, TreeSet stores the elements in an ascending order and retrieval speed of an element out of a TreeSet is faster. The TreeSet class internally uses a TreeMap to store elements. The elements in a TreeSet are sorted according to their natural ordering. We can also save the elements stored in a TreeSet to a file by using the Arrays.asList() method and pass this set as an argument to the writeObject() method of ObjectOutputStream class. Syntax public class TreeSet extends AbstractSet implements NavigableSet, Cloneable, Serializable Example import java.util.*; import java.io.*; public ...
Read MoreWhen can we use the getClass() method in Java?
The getClass() method is from Object class and it returns an instance of the Class class. When we declare a new instance of an object, it will be referring to a class. There can only be one class per JVM but multiple object referring to it. So when we get the class of two objects, they might be referring to the same class. Syntax public final Class getClass() Example class User { private int id; private String name; public User(int id, String name) { this.id = id; this.name ...
Read More