Skip to main content

Constructor-1

Constructor:-Constructor is a special type of method which does not have any return type not even void, Constructor is used for instantiation of class. Constructor having some special properties that are given below.

1)      The name of constructor must be same as class name
2)      Constructor must write inside class
3)      Constructor may be multiple type
4)      Constructor can be overloaded
5)      Constructor cannot inherit
6)      All four access modifiers can use for constructor
7)      Constructor cannot call
8)      Constructor automatically invoke at the time of object creation

Example1:- Single constructor with default modifier.

class Student
{
Student()
{
System.out.println("This is constructor");
}
public static void main(String[]args)
{
Student s1=new Student(); 
}
}

Output:-
 C:\JAVATECH>javac Student.java
C:\JAVATECH>java Student

This is constructor

Example2:- Single constructor with default modifier but more object created.

class Student
{
Student()
{
System.out.println("This is constructor");
}
public static void main(String[]args)
{
Student s1=new Student(); 
Student s2=new Student(); 
Student s3=new Student(); 
}
}

Output:-
C:\JAVATECH>javac Student.java
C:\JAVATECH>java Student

This is constructor
This is constructor
This is constructor


Example3:- Single constructor with default modifier but more object created.

class Student
{
static int i=0;
Student()
{
i++;
System.out.println(i+" Object created");
}
public static void main(String[]args)
{
Student s1=new Student();
Student s2=new Student();
Student s3=new Student();
}
}

Output:-
C:\JAVATECH>javac Student.java
C:\JAVATECH>java Student

1 Object created
2 Object created
3 Object created


Example4:-Multiple Constructor-1.

class Student
{

Student()
{
System.out.println("Zero argument Constructor");
}
Student(int a)
{
System.out.println("Parameterized Constructor");
}
public static void main(String[]args)
{
Student s1=new Student();
Student s2=new Student(10);
}
}

Output:-

C:\JAVATECH>javac Student.java
C:\JAVATECH>java Student

Zero argument Constructor
Parameterized Constructor

Example5:-Multiple Constructor-2.

class Student
{

Student()
{
System.out.println("Zero argument Constructor");
}
Student(int a)
{
System.out.println("Parameterised Constructor");
}
Student(Student t)
{
System.out.println("Parameterised Copy Constructor");
}
public static void main(String[]args)
{
Student s1=new Student();
Student s2=new Student(10);
Student s3=new Student(s2);
}
}

Output:-

C:\JAVATECH>javac Student.java
C:\JAVATECH>java Student

Zero argument Constructor
Parameterised Constructor

Parameterised Copy Constructor


Labels:

Comments

Post a Comment

Popular posts from this blog

Introduction of Java

Java is a high level programming language which is used for creating various types of software's or applications. Types of java applications:- 1)     Stand alone application 2)     Desktop based application          3)     Web based application 4)     Enterprise application etc. Stand alone application:- Stand alone application run on single machine without user interface and every stand alone application having main method. Desktop based application:- Desktop based application also run on single machine with user interface and every Desktop based application having main method. Web based application:- Web based application run on web, web based application not required main method but for such types of application need server. Enterprise application:- Enterprise application is category of web application where doing some business or involve some money related issues. Java Editions: - There are four Java platforms. ·       
2 comments
Read more

Small concept about OOPs

Some small concept about OOPs:- In many books and website write about OOPs concepts as hundred percent object oriented, pure object oriented and partial object oriented language. Hundred percent object oriented:- In the hundred percent object oriented movie hero is object, without object program is incomplete that means can not execute program without object. Without class and object programming or application development is not possible. Example of hundred percent object oriented language is  Smalltalk . Pure object oriented:- In the object oriented cinema obviously object is the hero. In pure object oriented language object having same importance but in this having some relax that is without creating object we can successfully execute our application. So in the object oriented programming without class we cannot create or run our application, class is must. Example of pure object oriented language is  Java . Partial object oriented:- In this type of language cl
Post a Comment
Read more

java print

Syntax of main method in java is    public static void main(String[]args)  before understanding about main method we have to understand that who is responsible for main method.if we write a simple program or write a simple java class without main method like      Test.java           class Test      {      } above program will compile successfully.for compilation of  java file use  javac tool  or  javac.exe  file. javac Test.java it means compiler checks only syntax of class that means compiler does not check the main method in the file or program,so that compiler is not responsible for main method in java. After successfully compilation of above program we have to run the generated byte code. java Test Error: Main method not found in class Test, please define the main method as:    public static void main(String[] args) So JVM (java virtual machine) or java interpreter is responsible for main method,first jvm check that the main method is pres
Post a Comment
Read more