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Java Articles
Page 149 of 450
Reading data from keyboard using console class in Java
The Console class is part of the Java.io package and is used to read input from the keyboard or user and write output to the console. Unlike Scanner, the Console class provides methods to read text and passwords. If you read a password using the Console class, it will not be displayed to the user (without showing the typed characters). To use the Console class, we need its object, and the Console object is obtained by calling System.console() as shown below - Console console = System.console(); Note: If you try to execute the program in a non-interactive environment like an IDE, it doesn’t work. It ...
Read MoreHow to set a tooltip text for each item of a JList in Java?
In this article, we will learn to set a tooltip text for each item of a JList in Java. Tooltips give meaningful information as users hover over UI components. Swing's JList does not support tooltips on a per-item basis, so it will involve some customization. What is JList? A JList is a subclass of the JComponent class, and it can be used to display a list of objects that allows the user to select one or more items. A JList can generate a ListSelectionListener interface and needs to implement the abstract method valueChanged(). Syntax The following is the syntax for ...
Read MoreHow to Write/create a JSON file using Java?
In this article, we will learn to write/create a JSON file using Java. JSON has become the standard for data exchange for any kind of application. Java also has a collection of libraries helpful in creating and storing JSON files. JSON JSON or JavaScript Object Notation is a lightweight text-based open standard designed for human-readable data interchange. Conventions used by JSON are known to programmers, which include C, C++, Java, Python, Perl, etc. Sample JSON document Below is an example of a JSON file: { "book": [ { ...
Read MoreWhen will be an IllegalStateException (unchecked) thrown in Java?
In this article, we will learn how an IllegalStateException (unchecked) is thrown in Java. IllegalStateException is a subclass of RuntimeException. It occurs when a method is used at the wrong time or when an object is not in the right state. What is an IllegalStateException? An IllegalStateException is an unchecked exception in Java. This exception may arise in our Java program mostly if we are dealing with the collection framework of java.util.package. There are many collections, such as List, Queue, Tree, and Map, of which List and Queues (Queue and Deque) throw this IllegalStateException under particular conditions. When will ...
Read MoreConvert List of Characters to String in Java
In this article, we will learn to convert a list of characters to strings in Java. Sometimes, when we handle character-based data structures, we need to convert a list of characters into a string. Problem Statement Given a list of characters, the task is to convert it into a single string where the order of characters remains unchanged. Input: list = Arrays.asList('W', 'e', 'l', 'c', 'o', 'm', 'e'); Output: Welcome Methods to Convert a List of Characters to a String The following are the different approaches to convert a list of characters to a string in Java - ...
Read MoreHow can we set a border to JCheckBox in Java?\\n
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 MoreHow can we set the shortcut key to a JButton in Java?
In this article, we will learn to set the shortcut key to a JButton in Java. In Swing-based applications, we can implement the addition of keyboard shortcuts to buttons to enable quicker navigation by the user. What is a JButton? A JButton is a subclass of AbstractButton, and it can be used to add platform-independent buttons to a Java Swing application. When the button is pressed or clicked, a JButton can generate an ActionListener interface; it can also generate the MouseListener and KeyListener interfaces. Setting the Shortcut Key for JButton We can also set the shortcut keys for a JButton ...
Read MoreHow can we implement the word wrap JTableHeader of a JTable in Java?
In this article, we will learn to implement the word wrap JTableHeader of a JTable in Java. The Java Swing default JTableHeader does not support word wrapping. This is a problem if you have long column headers. We can implement this by customizing the DefaultTableModel class or the AbstractTableModel class. JTableHeader A JTableHeader is a subclass of the JComponent class. When we create a JTable object, the constructor creates a new JTableHeader object to manage the table component's header. Syntax The following is the syntax for JTableHeader Declaration: public class JTableHeader extends JComponent The JTableHeader object is associated with ...
Read MoreHow to read/parse JSON array using Java?
In this article, we will learn to read/parse a JSON array using Java. A JSON array is an ordered collection of values that are enclosed in square brackets, i.e., it begins with ‘[’ and ends with ‘]’. The values in the arrays are separated by ‘, ’ (comma). Sample JSON array The following is the syntax for JSON array initialization: { books": [ Java, JavaFX, Hbase, Cassandra, WebGL, JOGL] } Reading (Parsing) JSON array in Java The following are the different approaches for reading/parsing a JSON array in Java: JSON-Simple maven dependency ...
Read MoreHow to print the first character of each word in a String in Java?
This article will discuss how to print the first character of each word in a given string. For example, if we have the string "Hello John", the output should be H J. In Java, the String class is used to represent character strings. All string literals in a Java program are implemented as instances of the String class. Strings in Java are immutable, which means that once a string is created, its value cannot be changed. To print the first character of each word in a String, we have the following approaches - Using split() ...
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