java creating object constructor

First of all you will have to create file with .java extension with class name same with the file name


as show in the program given



/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

package javaapptwo;

/**
 *
 * @author jawadmahmood
 */
public class Student {
    private String name ;
   
    private int rollNo ;
   
   
    public void setName(String name)
    {
        this.name  = name;
    }
   
    public void setRollNo(int rollNo)
    {
        if(rollNo > 0 )
        {
            this.rollNo = rollNo;
           
        }
        else
        {
           this.rollNo = 100;
        }
    }
   
    public String getName()
    {
        return name ;
    }
   
    public int getRollNo()
    {
        return rollNo;
    }
   
   
    public Student()
    {
        name  = "not defined";
        rollNo = 500;
    }
   
    public Student(String name , int rollNo)
    {
        setName(name);
        setRollNo(rollNo);
       
    }
   
    public Student(Student s)
    {
        name = s.name;
       
        rollNo = s.rollNo;
    }
   
    public void print()
    {
        System.out.println("Student name: " + name + " ,  RollNo " + rollNo);
    }
}

as image given

and will have to create the class with main method

/*

 * To change this license header, choose License Headers in Project Properties.

 * To change this template file, choose Tools | Templates

 * and open the template in the editor.

 */

package javaapptwo;

/**

 *

 * @author jawadmahmood

 */

public class JavaAppTwo {

    /**

     * @param args the command line arguments

     */

    public static void main(String[] args) {

        // TODO code application logic here

        

        System.out.println("Welcom");

        

        Student s1 = new Student("ali" , 15);

        Student s2 = new Student();

        Student s3 = new Student("akhtar khan ", 55); 

        s1.print(); 

        s2.print(); 

        s3.print();

        

    }

    

}

image

now run the program 

and you will get the result as