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#Java constructor method code

If we do not provide an user-defined constructor in a class, the compiler initializes member variables to its default values such as:

#Java constructor method code

This default constructor is not present in your source code or the java file as the compiler automatically puts it into the Java code during the compilation process and therefore we can’t find it in our java file, rather it exists in the bytecode or. The Java compiler automatically creates a default constructor if we do not write any constructor in our program.

Default ConstructorĪ Default Constructor is a constructor with no parameter. Let’s discuss each of them with examples: 1. There are two types of constructors in Java, which are: In the above line, the new keyword creates the object of class M圜lass and invokes or calls the constructor to initialize this newly created object. When we initialize or create the object of M圜lass it looks like this: M圜lass obj = new M圜lass() Let’s take an example to understand the working of a constructor. Note that the constructor name matches the class name and it is without a return type.

We can not declare a constructor as final, abstract, abstract and synchronized.Ī constructor has the same name as the class and we can write a constructor as follows: public class M圜lass.

We can use the access modifiers with a constructor to control its access so that other classes can call the constructor.

It can not have not even void as its return type.

A constructor must have no return type.

The name of the constructor must be the same as the name of its class.

Rules for Writing Constructors in Javaįollowing are some rules for writing constructors in Java: We can create a constructor either explicitly through programming and if we do not define it explicitly, the Java compiler itself defines the default constructor. The constructors allow us to define the values while creating the objects. Can we define an Apple with no value defined for its properties? We can definitely not do this. But, when we create an object of the class Apple, now Apple will reside in the computer’s memory. If we create a class named Apple, then it will have some class variables like shape, color, and taste. To understand the importance of constructors, let’s take an example. We can use the constructors when we want to assign values to the class variables at the time of object creation. If we do not write any constructor in the class then the default constructor is called.

Note: When we create an object of a class, at least one constructor is called. It is not necessary for Java coders to write a constructor for a class. The name of the constructor is the same name as that of the class and its primary job is to initialize the object with a legal initial value for the class. It is a special type of method that instantiates a newly created object and just after the memory allocation of this object takes place, the constructor is called. “A Constructor is a member function which has the same name as its class and is used to initialize the object of that class type with the legal initial value.”Ī constructor is a member function of a class that is called for initializing objects when we create an object of that class. Keeping you updated with latest technology trends, Join TechVidvan on Telegram Constructor in Java