Constructor Chaining In Java with Examples. Prerequisite Constructors in Java. Constructor chaining is the process of calling one constructor from another constructor with respect to current object. Constructor chaining can be done in two ways Within same class It can be done using this keyword for constructors in same class. From base class by using super keyword to call constructor from the base class. Download Factorial program class file. Output of program You can also find factorial using recursion, in the code fact is an integer variable so only factorial of. Output of program When cpp object is created default constructor is called and when java object is created constructor with argument is called, setName method is. Constructor chaining occurs through inheritance. A sub class constructors task is to call super classs constructor first. Java is a programming language created by James Gosling from Sun Microsystems Sun in 1991. The target of Java is to write a program once and then run this program. This Java class example describes how class is defined and being used in Java language. Prerequisite Constructor, Overloading in java. In addition to overloading methods, we can also overload constructors in java. Overloaded constructor is called. Core Java Interview Questions and Answers for Beginner, Advanced Experienced programmers from my 10 years of java programming and interviewing experience. Today I want to introduce the topic of Java multithreading to you. This is a bit of an advanced topic, so if you are not familiar with Java programming, I. The compiler may have to allocate a temporary variable to hold the value of i 1, which means the postfix version might be slower. How to get the memory. This topic will discuss this keyword in Java. What is the purpose of this keyword and how to use it. Constructor Program In Java' title='Constructor Program In Java' />This ensures that creation of sub classs object starts with the initialization of the data members of the super class. There could be any numbers of classes in inheritance chain. Every constructor calls up the chain till class at the top is reached. Why do we need constructor chaining This process is used when we want to perform multiple tasks in a single constructor rather than creating a code for each task in a single constructor we create a separate constructor for each task and make their chain which makes the program more readable. Constructor Chaining within same class using this keyword. Java program to illustrate Constructor Chaining. Using this keyword. System. out. printlnThe Default constructor. Tempint x. calls constructor 3. System. out. printlnx. Tempint x, int y. System. out. printlnx y. String args. invokes default constructor first. Temp. Output The Default constructor. Rules of constructor chaining The this expression should always be the first line of the constructor. There should be at least be one constructor without the this keyword constructor 3 in above example. Constructor chaining can be achieved in any order. What happens if we change the order of constructors Nothing, Constructor chaining can be achieved in any order. Java program to illustrate Constructor Chaining. Best Spyware Adware Program'>Best Spyware Adware Program. Using this keyword. System. out. printlndefault. Tempint x. invokes default constructor. System. out. printlnx. Tempint x, int y. System. out. printlnx y. String args. invokes parameterized constructor 3. Temp8, 1. 0. NOTE In example 1, default constructor is invoked at the end, but in example 2 default constructor is invoked at first. Hence, order in constructor chaining is not important. Constructor Chaining to other class using super keyword. Java program to illustrate Constructor Chaining to. String name. constructor 1. System. out. printlnNo argument constructor of. BaseString name. System. Calling parameterized constructor. Derived extends Base. System. out. printlnNo argument constructor. DerivedString name. System. out. printlnCalling parameterized. String args. calls parameterized constructor 4. Derived obj new Derivedtest. Calls No argument constructor. Derived obj new Derived. Free Integration By Parts Ti 84 Program Programs'>Free Integration By Parts Ti 84 Program Programs. Output Calling parameterized constructor of base. Calling parameterized constructor of derived. Note Similar to constructor chaining in same class, super should be the first line of the constructor as super classs constructor are invoked before the sub classs constructor. Alternative method using Init block When we want certain common resources to be executed with every constructor we can put the code in the init block. Init block is always executed before any constructor, whenever a constructor is used for creating a new object. Breville Nutri Steam Manual. Example 1. block to be executed before any constructor. System. out. printlninit block. System. out. printlndefault. Tempint x. System. Object creation by calling no argument. Temp. Object creation by calling parameterized. Temp1. 0. Output init block. NOTE If there are more than one blocks, they are executed in the order in which they are are defined within the same class. See the ex. Example. System. out. printlninit. System. out. printlndefault. Tempint x. System. System. out. printlnsecond. String args. new Temp. Temp1. 0. This article is contributed by Apoorva singh. If you like Geeksfor. Geeks and would like to contribute, you can also write an article using contribute. See your article appearing on the Geeksfor. Geeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.