Immutable Object: An object is known as immutable if its state can not be changed over time or we can say after object creation. Need for Immutable Classes In current days, most of the applications are running into multi-threading environments which results in concurrent modification problems. Popular Immutable classes in java All wrapper classes (java.lang.Integer, … Read more
A substring is a string that is part of a longer string. String class provides the following methods to get a substring from a string. 1. public String substring(int startIndex): Returns a new string that starts from a specified string and extends to the end of this string. It will throw IndexOutOfBoundsException – if startIndex … Read more
The general meaning of concatenation is a series of interconnected things. String concatenation refers to the combination of more than one string. Ways of String concatenation: By concatenation operator +. By concat() method. 1. By concatenation operator + String concatenation can be performed with the + operator. String concatenation is performed by the StringBuilder or … Read more
In Java, there are three ways to compare two strings. Ways of String Comparison By == operator. By equals() method. By compareTo() method. 1. By == operator == operator compares the references of the string objects not the actual content of the string objects. It returns true if references of the compared strings are equal, … Read more
String handling is a way of handling and manipulating strings in java with the help of a lot of concepts like concatenation, comparison, etc. String: In General – A string is a sequence of characters. In Java – A string is an object which is created by using the String class. String objects are immutable … Read more
final is a keyword in Java that can be used with instance variables, local variables, methods, and classes. Use of final keyword in Java 1. final variable in Java A variable declared with the final keyword is known as the final variable. It may be a member variable or a local variable. final variables … Read more
Static is a keyword in Java used to represent the class members. It can be used with variables, methods, initializer blocks, and nested classes. Types of class members: Static data members. Static initializer block. Static method. Static nested class. 1. Static data members: Data members declared with static keywords are known as static data members. … Read more
Super is a keyword in Java that refers to the immediate superclass object. Use of super keyword in Java: super can be used to call the immediate super class constructor (constructor chaining). super can be used to call an immediate superclass method on a subclass object from a subclass method. super can be used to … Read more
Java Instance Initializer block is a mechanism provided by the Java compiler to define a group of statements common to all constructors in a single place. At the compilation time, the compiler moves these statements at the beginning of all constructors after super. It can also be used to initialize the instance variable. Java Instance … Read more
Java this keyword refers to the current instance of the class. Every constructor and all non-static methods in Java have this as an implicit parameter. Note: When n numbers of parameters are passed in a method then from the JRE point of view n+1 number of parameters are passed in the method. One additional parameter … Read more