Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
An interface in Java is a specification of method prototypes. Whenever you need to guide the programmer or make a contract specifying how the methods and fields of a type should be, you can define an interface. When a class implements an interface, it should provide concrete implementations for all of its abstract methods. But is it possible to override only one method from an interface? Overriding a Method from an Interface In Java, all methods in an interface are abstract (unless declared as default or static). When a class implements an interface, it must override those abstract methods. No, ... Read More
Sorting a string alphabetically means rearranging its characters in order, from A to Z. For example, the string "java" becomes "aajv" after sorting. Different ways to sort a String Alphabetically There are two ways to do this in Java using different approaches - Using toCharArray() and Arrays.sort() Method Sorting the array manually Using toCharArray() and Arrays.sort() Method The toCharArray() method of this ... Read More
In Java, the collections framework provides various classes like ArrayList, HashSet, and LinkedList to store groups of elements. But once data is stored, how do you access or retrieve it? Java provides multiple ways to retrieve elements from collections, depending on whether you're reading values, modifying them during traversal, or iterating forward or backward. You can retrieve the elements of a collection in four ways- Using For-Loop Using For-Each Loop ... Read More
When working with collections in Java, you might need to convert an array to an ArrayList. This is useful because ArrayList offers more flexibility, such as dynamic sizing and built-in methods for adding, removing, and searching elements. Need for Converting an Array to an ArrayList Arrays in Java have a fixed size and provide limited functionality. ArrayList, on the other hand, is part of the Java Collections Framework and provides methods to modify data dynamically. It is useful when - Need to use dynamic Collections. ... Read More
When you are working with strings in Java, you may want to keep only the alphabetic characters (A-Z, a-z) and remove everything else, like numbers, punctuation, and symbols. Java gives you multiple ways to do this for different cases or scenarios. Removing non-alphabetical characters from a string There are different methods, and they are - Using split() method Using replaceAll() method ... Read More
In this article, we will learn how to convert a JSON string to a Java object using the json.simple library. JSON stands for JavaScript Object Notation. It's a simple format that stores data in key-value pairs. It is used for sharing data between a server and a web app. To learn more about JSON, you can refer to the JSON tutorial. In Java, we can use a library called json.simple to handle JSON data. So, using this, we can easily convert a JSON string into a Java object. Why Convert JSON String to Java Object? There are many reasons to ... Read More
In this article, we will learn how to construct a JSON object from a subset of another JSON object in Java. If you are not familiar with JSON and its usage in Java, you can refer to our JSON Overview tutorial. JSON Object From a Subset of Another Object There is more than one way to construct a JSON object from a subset of another JSON object in Java. Some of the popular libraries that we can use are - Using org.json library Using Gson library Using ... Read More
In this article, we will learn about the differences between a MouseListener and a MouseMotionListener in Java. We can implement a MouseListener interface when the mouse is stable while handling the mouse event, whereas we can implement a MouseMotionListener interface when the mouse is in motion while handling the mouse event. Mouse Listener A MouseListener is fired when we press, release or click (press followed by release) a mouse button (left or right button) at the source object or position the mouse pointer at (enter) and away (exit) from the source object. Abstract Methods A MouseListener interface declares the following five ... 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 this article, we will learn about the importance of the FocusListener interface in Java. In Java, the FocusListener Interface plays an important role in making GUIs interactive and responsive. It enables the developer to monitor and respond to changes in focus in a Java-based application. FocusListener The focus events are generated whenever a component gains or loses keyboard focus. The Objects representing focus events are created from the FocusEvent Class. The corresponding listener interface for the FocusEvent class is the FocusListener interface. Each listener for FocusEvent can implement the FocusListener interface. Syntax The following is the syntax of the ... Read More