java constructor not called in main class

#JAVA CONSTRUCTOR NOT CALLED IN MAIN CLASS HOW TO#

declare method to calculate area of rectangle declare constructor to initialize length and breadth of rectangle

#JAVA CONSTRUCTOR NOT CALLED IN MAIN CLASS HOW TO#

Let us consider the program that gives us the use of constructor to initialize the instance variables of the newly created object.įirstly we make a class Rectangle in which we declare constructor and method to show how to use it: //use of constructor Each parameter specification, if any, consists of a type and a name and are separated from each other by commas. The parameterList is the list of optional zero or more parameters that are specified after the class name in the parenthesis. Here, the constructorName is same as the name of class it belongs to. The syntax of constructor is as follows: ConstructorName() This is accomplished using a special method in java known as constructor that makes an object to initialize itself at the time of its creation without the need to make separate call to the instance method. This would be inconvenient if the number of objects is very large.Ī better solution to the above problems is to initialize values to the object at a time of its creation in the same way as we initialize values to the variable of primitive data types. But it would have to be called explicitly for each object. In second approach we make use of method to assign values to fields of each object individually.Moreover, it does not promote data hiding. However it can be tedious job to initialize the instance variables of all objects individually. In the first approach we use a dot operator to access and assign values to the instance variables for each object individually.It can be done by using following two approaches: In object oriented programming language (OOPL) like java, the need of initialization of fields of a new object is even more common. We can initialize variables of primitive types at the time of their declarations. Initializing a variable is very helpful while making programs. 8 Important Points to Remember About Constructor:.

Java constructor not called in main class