Java

In Java, Strings are immutable which means that the existing String objects can't be changed i.e we can't modify the existing String objects or we can't change the internal state of the String objects.

Java has three sets of control statement that might be utilized to change the progression of execution of a program. The first set of statements is called selection statements followed by iteration statements and jump statements.

Command pattern is a behavioral-based design pattern that encapsulates a request/action in an object without knowing the internal operations. We have explored it in depth in Java.

Covariant return type in an Object oriented programming language means that the return type of any method can be replaced by a narrower type when it is overridden in the subclass or child class. We have explored it in Java in depth.

Java is an Object Oriented Programming language and supports the feature of inheritance. We cannot have Multiple Inheritance in Java directly due to Diamond Problem but it can be implemented using Interfaces.

In this article, we have explored how to make a Java code execute faster by handling Input and Output better. The ways we presented are Scanner class, BufferedReader class, User-defined FastReader Class and Reader Class.

The java.lang.String class provides a lot of methods to work on string. By the help of these methods, we can perform operations on string such as trimming, concatenating, converting, comparing, replacing strings etc. We have explored it in detail.

The 'this' keyword in Java is a reference ( which means it manages some relation ) to the current object where it is called. We have presented 6 usage of this keyword which includes referring to current class instance variable and much more.

In this article, we have explored Singleton design pattern in Java in depth and demonstrated several approaches each with its own advantages and shortcoming. We have explored related concepts like early and late initialization as well.

The three main elements of an exception handler in Java are: try, catch and finally block. We have explored these in depth with examples and questions related to handling exceptions in Java.

Super keyword, in Java, is used to call the Constructor of the Parent Class. It is required when we need to pass some arguments to Parent Class and complete object instantiation.

in this article, we have explored the basics of Abstract Window Toolkit (AWT) in Java which is used for creating Windows based Graphical User Interface. We demonstrated it by implementing a form UI using AWT in Java.

In this article, we have focused on 2D array in Java which is a variant of the usual 1D array by introducing a new dimension. We have demonstrated different operations with 2D arrays.

An Array List is a dynamic version of array and is supported in Java's collection library. In this article, we have focused on 2D array list in Java along with different methods applicable on it like indexOf.

In this article, we have explored the different types of exceptions in Java. The main types are checked and unchecked exceptions. By definition, the types are build-in exceptions and user defined exceptions.

In this article, we have explored how to find if two strings are equal in Java. There are three ways to check if two strings in Java are equal by == operator, equals() method and compareTo() method.

Lambda expressions were added in Java 8 along with functional programming. Before understanding lambda expressions or lambdas for short, a prerequisite is to understand what is a Functional Interface.

JUnit testing is the unit testing framework for Java. We have explored JUnit testing using Maven in depth with a code example in this article.

Enum in Java is a special type of a class which can have constructors,methods, and instance variables. Enum contains a fixed set of constant. In Java, a list of predefined values can be created using enums.

In this article at OpenGenus, we are going to discuss how to create and delete folders in Java. Folders are called directories in Java and we will do this using java.io package.

In Java, inner class is a nested class which is defined within another class and it provides better encapsulation. There are several variants like anonymous inner class, method local inner class and much more.

Java handles input and output through streams and there are multiple input and output streams specialized for different use cases like BufferedOutputStream and much more which we have explored in depth in this article at OpenGenus.

In Java, we can compare String using ==, equals() and equalIgnoreCase() and each has different results. We have explained it in detail in this article.

In the context of Java Inheritance, final and abstract are two important modifiers on deciding whether a class can take part in an inheritance relationship or not.