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Java Articles
Page 158 of 450
Remove all non-alphabetical characters of a String in Java?
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 MoreHow to construct a JSON object from a subset of another JSON object in Java?
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 MoreWhat are the differences between a MouseListener and a MouseMotionListener in Java?
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 MoreDifference Between LinkedList and LinkedHashSet in Java
LinkedList and LinkedHashSet are two important classes of Java's Collection framework. They are used to store groups of items, but they work in different ways and have their own unique features. What is a LinkedList in Java? Java LinkedList is a linear data structure that is used to store the same type of elements. It is a part of the Java Collections Framework, and it implements the List as well as the Deque interfaces. It has a dynamic size, which means it can grow and shrink as needed. Example The following is an example of how we write code for ...
Read MoreWhy can\'t a Java class be both abstract and final?
In Java, both abstract and final are class modifiers but they are completely opposite to each other. That's why Java class cannot be both abstract and final. Abstract class An abstract class in Java is a class that may contain both abstract methods (without implementation) and concrete methods (with implementation). If a class has even one abstract method, it must be declared abstract. You cannot create objects of an abstract class directly. If you want to use the concrete method in an abstract class you need to inherit the class, provide implementation to the abstract methods (if any) and ...
Read MoreCan Enum extend any class in java?
If you’ve been coding in Java for some time, you might have wondered why you can't make an enum extend another class. It seems like it should, but Java won't let you. Let's break down why this happens Enumeration in Java Enumeration (enum) in Java is a user-defined datatype which stores a set of constant values. You can use enumerations to store fixed values such as days in a week, months in a year, and seasons, etc. If we had to store all seven days of a week into one single variable then we might tend to use data ...
Read MoreHow to read a .txt file with RandomAccessFile in Java?
In general, while reading or writing data to a file, you can do so, from the start of the file. You cannot read/write from random position. The java.io.RandomAccessFile class in Java enables you to read/write data to a random-access file. This acts similar to a large array of bytes where the cursor known as file pointer works like an index. With the help of file pointer you can get the position of this pointer using the getFilePointer() method and set it using the seek() method. RandomAccessFile Class: Reading Files This class provides various methods to read and write data ...
Read MoreJava program to check if string is pangram
The given task is to write a Java program to check whether a string is a pangram or not. A string is called a pangram if and only if it contains all the letters of the English alphabet, regardless of their case. Example Scenario:Let's understand the problem with an example - Input: "The quick brown fox jumps over the lazy dog" Output: Yes, the string is a pangram Read the input String, you can find all the letters of the English alphabet in it. Therefore, it is a pangram string. How to Check if a String is a Pangram ...
Read MoreHAS-A relationship in Java
Java is a programming language that follows the Object-Oriented Programming paradigm. One of the pillars of OOPs is Inheritance, where you can find a relationship between two classes as Parent and Child. This relationship allows these classes to reuse each other's attributes and methods. Java classes can relate to each other in many ways such as, Is-A relationship and Has-A relationship. In this article, we are going to learn the concept of Has-A relationship in Java through examples. HAS-A Relationship in Java Has-A relationship is a type of association where two classes are linked to each other through objects. Here, ...
Read MoreHAS-A relationship in Java
Java is a programming language that follows the Object-Oriented Programming paradigm. One of the pillars of OOPs is Inheritance, where you can find a relationship between two classes as Parent and Child. This relationship allows these classes to reuse each other's attributes and methods. Java classes can relate to each other in many ways such as, Is-A relationship and Has-A relationship. In this article, we are going to learn the concept of Has-A relationship in Java through examples. HAS-A Relationship in Java Has-A relationship is a type of association where two classes are linked to each other through objects. Here, ...
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