Task - Constructors and Encapsulation - An Student

[akash-coded]

Create a class Student with the following data members:

  private int rollNo
  private String name

Implement the following in the Student class:

• All the possible overloaded constructors
• Use 'this' keyword in parameterized constructors
• Define a function getRollNo() which returns the rollNo of the student
• Define a function getName() which returns the name of the student
• Define a function setRollNo() which accepts an integer parameter rollNo and updates the rollNo of a student
• Define a function setName() which accepts a String parameter name and updates the name of a student
• A function display() that displays all the details of a student.

Create a driver class StudentDriver with the main() method to implement the above features.

[Mrafe]

`class Student {
private int rollNo;
private String Name;

Student() {
    rollNo = 1;
    Name = "New Student";
}

Student(int rollNo, String Name) {
    this.rollNo = rollNo;
    this.Name = Name;
}

Student(int rollNo) {
    this.rollNo = rollNo;
}

Student(String Name) {
    this.Name = Name;
}

int getRollNo() {
    return rollNo;
}

String getName() {
    return Name;
}

void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

void setName(String Name) {
    this.Name = Name;
}

void display() {
    System.out.println("The roll no of : " + Name + " is " + rollNo);
}

}

class C202 {
public static void main(String[] args) {
Student student1 = new Student();
Student student2 = new Student(2, "Kaneko");
Student student3 = new Student(3);
Student student4 = new Student("Nezuko");
student3.setName("Asuna");
student4.setRollNo(4);
int roll1 = student1.getRollNo();
String name2 = student2.getName();
System.out.println("The roll number of student 1 is " + roll1);
System.out.println("The Name of student 2 is " + name2);
student3.display();
student4.display();
}
}`

[RohitNaikade1]

class Student{

int rollNo;
String name;
Student(){
    rollNo=110;
    String name="Rohit";
}

Student(int rollNo){
    this.rollNo=rollNo;
    this.name = "Default";
}
Student(String name){
    this.name = name;
    this.rollNo=0;
}
Student(int rollNo,String name){
    this.rollNo = rollNo;
    this.name = name;
}

protected void display(){
    System.out.println("RollNo: "+this.rollNo);
    System.out.println("Name: "+this.name);
}

protected int getRollNo(){
    return this.rollNo;
}
protected String getName(){
    return this.name;
}
protected void setRollNo(int rollNo){
    this.rollNo=rollNo;
}
protected void setName(String name){
    this.name=name;
}

}

public class Constructor {

public static void main(String[] args) {
    
    Student s1=new Student(10,"Omkar");
    Student s2=new Student(20);
    Student s3=new Student("Piyush");
    Student s4=new Student();

    s1.display();
    s2.display();
    s3.display();
    s4.display();
    s2.setName("Mehul");
    s3.setRollNo(339);

    s2.display();
    s3.display();
}

}

[preeti-max]

`class Student{
private int rollno;
private String name;
Student(){
this.rollno = 0;
this.name = "Student";
}
Student(int rollno,String name){
this.rollno = rollno;
this.name = name;
}
Student(int rollno){
this.rollno = rollno;

}
Student(String name){
    this.name = name;
}
protected void display(){
    System.out.println("Roll no. :"+rollno);
    System.out.println("Name: "+name);
}
protected int getRollno(){
    return rollno;
}
protected String getName(){
    return name;
}
protected void setRollno(int rollno){
    this.rollno = rollno;
}
protected void setName(String name){
    this.name = name;
}

}
class Constructor{

public static void main(String[] args) {
    Student s1,s2,s3,s4;
     s1=new Student();
     s2=new Student(101,"Preeti");
     s3=new Student(102);
     s4=new Student("Rahul");
     s3.setName("Ankita");
     s4.setRollno(104);
     s1.getName();
     s1.getRollno();
     s2.display();
     
}

}

`

[ratnadeepikavuddagiri]

`class Student {
private int rollNo;
private String name;

Student() {
    rollNo = 0;
    name = "New Student";
}

Student(int rollNo) {
    this.rollNo = rollNo;
    name = "New Student";
}

Student(String name) {
    rollNo = 0;
    this.name = name;
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

protected void display() {
    System.out.println("\nRoll Number : " + rollNo + "\nStudent Name : " + name);
}

int getRollNo() {
    return this.rollNo;
}

String getName() {
    return this.name;
}

void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

void setName(String name) {
    this.name = name;
}

}

public class StudentDetails {

public static void main(String[] args) {
    Student s1 = new Student();
    Student s2 = new Student(20);
    Student s3 = new Student("Jhansi");
    Student s4 = new Student(10, "Deepika");
    s1.display();
    s2.display();
    s3.display();
    s4.display();
    System.out.println(s2.getRollNo());
    System.out.println(s3.getName());
    s2.setName("Naga");
    s3.setRollNo(15);
    s1.display();
    s2.display();
    s3.display();
    s4.display();
}

}
`

[Sarfinaa]

`
class Student {
private int rollNo;
private String name;

Student() {
    this.rollNo = 1;
    this.name = "Karan";
}

Student(int rollNo) {
    this.rollNo = rollNo;
}

Student(String name) {
    this.name = name;
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

void display() {
           System.out.println("Name - " + getName() + "\nRoll No - " + getRollNo());
}

String getName() {
    return name;
}

int getRollNo() {
    return rollNo;
}

void setName(String name) {
    this.name = name;
}

void setRollNo(int rollNo) {
    this.rollNo = rollNo;

}

}

public class StudentInfo {
public static void main(String[] args) {
Student student1 = new Student();
Student student2 = new Student(2);
student2.setName("Shivam");
Student student3 = new Student(3, "Sagar");
Student student4 = new Student("Roger");
student4.setRollNo(4);
student1.display();
student2.display();
student3.display();
student4.display();

}

}
`

[Gaurav-Joshi-31]

Student class--
`
public class Student {
private int rollNo;
private String name;

Student() {
    rollNo = 21;
    name = "Gaurav";

}

Student(int rollNo) {
    this.rollNo = rollNo;
    name = "Gaurav";

}

Student(String name) {
    rollNo = 21;
    this.name = name;

}

Student(String name, int rollNo) {
    this.name = name;
    this.rollNo = rollNo;

}

public String getName() {
    return name;
}

public int getRollNo() {
    return rollNo;
}

public void setName(String name) {
    this.name = name;
}

public void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

public void display() {
    System.out.println("Name: " + name + "\nRoll No: " + rollNo);
}

}

`

Student Driver Class--

`
public class StudentDriver {
public static void main(String[] args) {
Student student1 = new Student();
Student student2 = new Student("MS Dhoni");
Student student3 = new Student(45);
Student student4 = new Student("Sachin", 11);

    student1.display();
    student2.display();
    student3.display();
    student4.display();

    student1.setRollNo(25);
    student1.display();

    student1.setName("Virat Kohli");
    student1.display();

    System.out.println(student4.getName());
    System.out.println(student3.getRollNo());

}

}
`

[ShraddhaPenshanwar]

`public class Student {
private int rollNo;
private String name;

Student() {
    rollNo = 0;
    name = "";
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;

}

Student(int rollNo) {
    this.rollNo = rollNo;
    // this.name=name;

}

Student(String name) {

    this.name = name;

}

public int getRollNo() {
    return this.rollNo;
}

public String getName() {
    return this.name;
}

public void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

public void setName(String name) {
    this.name = name;
}

public void display() {

    System.out.println("RollNo: " + rollNo + "  Name: " + name);

}

public static void main(String[] args) {

    Student s1 = new Student();
Student s2 = new Student(20);
Student s3 = new Student("Suresh");
Student s4 = new Student(1, "Ramesh");
s1.display();
s2.display();
s3.display();
s4.display();
System.out.println(s2.getRollNo());
System.out.println(s3.getName());
s2.setName("sharan");
s3.setRollNo(25);
s1.display();
s2.display();
s3.display();
s4.display();
}

}`

[sruthi-15-sketch]

class Student {
private int rollNo;
private String name;

Student() {
    rollNo = 597;
    name = "Indu";
}

Student(String name) {
    this.name = name;
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

Student(int rollNo) {
    this.rollNo = rollNo;
}

String getName() {
    return name;
}

int getRollNo() {
    return rollNo;
}

void setName(String name) {
    this.name = name;
}

void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

void display() {
    System.out.println("RollNo: " + this.rollNo);
    System.out.println("Name: " + this.name);
}

}

class Main {
public static void main(String[] args) {
Student s1 = new Student();
Student s2 = new Student(567, "Sruthi");
Student s3 = new Student(67);
Student s4 = new Student("Siva Sruthi");
System.out.println(s1.getName());
System.out.println(s1.getRollNo());
s2.setName("Sohan");
s3.setRollNo(77);
s1.display();
s2.display();
s3.display();
s4.display();
}
}

[ujjwal18bit1167]

` package Day5;

  class Student {
      private int rollNo;
      private String name;

Student() {
    System.out.println("This is default constructor ");
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

Student(int rollNo) {
    this.rollNo = rollNo;
}

Student(String name) {
    this.name = name;
}

void display() {
    System.out.println("Name : " + name);
    System.out.println("Roll No. " + rollNo);
}

int getRollNo() {
    return rollNo;
}

String getName() {
    return name;
}

void setName(String name) {
    this.name = name;
}

void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

}

 public class StudentUse 

{

      public static void main(String[] args) {
    Student s1 = new Student();
    Student s2 = new Student(25, "Ujjwal Gupta");
    System.out.println("Student2 's name is " + s2.getName());
    Student s3 = new Student(12);
    System.out.println("Student3's roll number is " + s3.getRollNo());
    Student s4 = new Student("Ujjwal Gupta");
    s4.setRollNo(55);
    System.out.println("Student4's roll number is " + s4.getRollNo());
}

}
`

[KaminiJha]

class Student{
private int rollNo;
private String name;
 Student()
 {
    rollNo=0;
    name="New Student";
 }
 Student(int rollNo)
 {
    this.rollNo=rollNo;
 }
 Student(String name)
 {
    this.name=name;
 }
 Student(int rollNo,String name)
 {
    this.name=name;
    this.rollNo=rollNo;
 }
 public void display()
 {
     System.out.println("Name is "+this.name+" and roll no is "+this.rollNo);
 }
 public int getRollNo()
 {
     return this.rollNo;
 }
 public String getName()
 {
     return this.name;
 }
 public void setRollNo(int newRollNo)
 {
     this.rollNo=newRollNo;
     System.out.println("RollNO updated successfully");
 }
 public void setName(String newName)
 {
     this.name=newName;
     System.out.println("Name updated successfully");
 }
}

public class Task1 {
    public static void main(String[] args) {
        Student s1=new Student();
        Student s2=new Student(12);
        Student s3=new Student("Kamini");
        Student s4=new Student(14,"Xyz");
        // System.out.println(s1.rollNo);->error bcz rollNo is private
        //set name in s1
        s1.setName("ABC");
        //set rollno in s2
        s2.setRollNo(15);
        //get rollno from s3
        System.out.println(s3.getRollNo());
        //get name from s4
        System.out.println(s4.getName());
        //display
        s1.display();
        s2.display();
        s3.display();
        s4.display();
    }
}

[Snehil6197]

class Student
{
private int roll_no;
private String name;

public Student()
{
roll_no=-1;
name="new name";
}

public Student(int roll_no)
{
this.roll_no=roll_no;
name="new name";
}
public Student(String name)
{
roll_no=-1;
this.name=name;
}

public Student(String name,int roll_no)
{
this.roll_no=roll_no;
roll_no=-1;
}

public int getRollNo()
{
return roll_no;
}

public String getName()
{
return name;
}
public void setName(String s)
{
name=s;
}

public void setRollNo(int r)

{
roll_no=r;
}

public void display()
{
System.out.println("RollNo is "+roll_no+" and name is "+name);
}
}

public class MyClass {
public static void main(String args[]) {
Student obj1=new Student();
obj1.display();
Student obj2=new Student("xyz",40);
obj2.display();
obj2.setName("hero");
obj2.display();
}
}

[karunakar23]

`
public class Student {
private int rollNo;
private String name;
Student(){
rollNo=-1;
name="New Student";
}
Student(int rollNo,String name){
this.rollNo = rollNo;
this.name = name;
}
Student(int rollNo){
this.rollNo = rollNo;
}
Student(String name){
this.name = name;
}
public int getRollNo(){
return rollNo;
}
public String getName(){
return name;
}
public void setRollNo(int rollNo){
this.rollNo = rollNo;
}
public void setName(String name){
this.name = name;
}
public void display(){
System.out.println("Name :"+name+" "+"rollNo :"+rollNo);
}
public static void main(String[] args) {
Student ram=new Student();
ram.setName("Ram");
ram.setRollNo(10);
ram.display();
Student ntr=new Student(1,"NTR");
ntr.display();
Student raju=new Student(2);
raju.setName("Raju");
raju.display();
}

}

`

[Amrit-Raj22]

class Student {
private int rollNo;
private String name;

protected void display() {
    System.out.println("name:" + name + "\nrollno.:" + rollNo);
}

protected void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

protected void setName(String name) {
    this.name = name;
}

protected String getName() {
    return this.name;
}

protected int getRollNo() {
    return this.rollNo;
}

///// constroctors/////
Student() {
    rollNo = 14;
    name = "Default";
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

Student(int rollNo) {
    this.rollNo = rollNo;
}

Student(String name) {
    this.name = name;
}

}

public class ClassStudent {
public static void main(String[] args) {
Student student1 = new Student();
Student student2 = new Student(2, "Student2");
Student student3 = new Student(3);
Student student4 = new Student("Student4");

    student1.display();
    student1.setName("Student1");
    student1.setRollNo(1);
    System.out.println(student1.getName());
    System.out.println(student1.getRollNo());
    student1.display();

    student2.display();
    student2.setName("NewStudent2");
    student2.setRollNo(12);
    System.out.println(student2.getName());
    System.out.println(student2.getRollNo());
    student2.display();

    student3.display();
    student3.setName("Student3");
    student3.setRollNo(13);
    System.out.println(student3.getName());
    System.out.println(student3.getRollNo());
    student3.display();

    student4.display();
    student4.setName("NewStudent4");
    student4.setRollNo(4);
    System.out.println(student4.getName());
    System.out.println(student4.getRollNo());
    student4.display();

}

}

[Batchusatyasri]

class Student {
private int rollno;
private String name;

Student() {
    rollno = 15;
    name = "satya";
}

Student(int rollno, String name) {
    this.rollno = rollno;
    this.name = name;
}

Student(int r) {
    rollno = r;
}

Student(String s) {
    name = s;
}

void display() {
    System.out.println("Student details" + " " + rollno + " " + name);
}

int getRollno() {
    return rollno;
}

String getName() {
    return name;
}

void setRollno(int rollno) {
    this.rollno = rollno;
}

void setName(String name) {
    this.name = name;
}

}

public class Students {
public static void main(String[] args) {
Student s1 = new Student();
System.out.println(s1.getRollno());
System.out.println(s1.getName());
Student s2 = new Student(20, "Lakshmi");
s2.display();
s2.setRollno(24);
s2.setName("Vyshnavi");
s2.display();
Student s3 = new Student(27);
Student s4 = new Student("Swathi");
s3.display();
s4.display();
}
}

[Shubhi27]

`
package session5;

class Student {
private int rollNo;
private String name;

Student() {
    rollNo = 5;
    name = "ABC";
}

Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
}

Student(int rollNo) {
    this.rollNo = rollNo;
    name = "Shubhi";
}

Student(String name) {
    rollNo = 55;
    this.name = name;
}

void display() {
    System.out.println("Rollno: " + rollNo + "\t" + "name: " + name);
}

public int getRollNo() {
    return rollNo;
}

public String getName() {
    return name;
}

public void setRollNo(int rollNo) {
    this.rollNo = rollNo;
}

public void setName(String name) {
    this.name = name;
}

}

public class Constructors {

public static void main(String[] args) {
    Student s1 = new Student();
    Student s2 = new Student(22, "Kohli");
    Student s3 = new Student(40);
    Student s4 = new Student("Shubhi");

    s1.display();
    s2.display();
    s3.display();
    s4.display();

    s1.setRollNo(25);
    s1.display();

    s1.setName("Virat Kohli");
    s1.display();

    System.out.println(s2.getName());
    System.out.println(s3.getRollNo());
}

}

`

[Karthick-code]

Student Details in Constructor

class Details{
    int rollno=0;
    String name=" ";
    public Details() {
    }
    public Details(int rollno) {
        this.rollno = rollno;
    }
    public Details(String name) {
        this.name = name;
    }
    public Details(int rollno, String name) {
        this.rollno = rollno;
        this.name = name;
    }
    
    public int getRollno() {
        return rollno;
    }
    public void setRollno(int rollno) {
        this.rollno = rollno;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    void display(){
        if(rollno==0){
            if(name.equals(" ")){
                System.out.println("Non parametarized constructor...");
            }
            else{
                System.out.println("Name: " + name);
            }
        }
        else{
            if(name.equals(" ")){
                System.out.println("Roll No : " + rollno);
            }
            else {
                System.out.printf("Name : %s%nRoll No : %d",name,rollno);
            }
        }
        System.out.println();
    }
}

public class Student{
    public static void main(String[] args) {
        Details d1=new Details();
        Details d2=new Details(123);
        Details d3=new Details("saran");
        Details d4=new Details(123,"sam");
        d1.display();
        d2.display();
        d3.display();
        d4.display();
        
    }
}

[Maha1805]

TASK-CONSTRUCTOR AND ENCAPSULATION

Student.java

import java.util.Scanner;

public class Student {
	private int rollNo;
	private String name;
	public Student() //non parameterized constructor
    {
        System.out.println("Student Details..");
    }
	public Student(int rollNo, String name) // parameterized constructor
        {
		super();
		this.rollNo = rollNo;
		this.name = name;
	}
	//getter and setter methods for accessing the private data members

	public int getRollNo() 
       {
		return rollNo;
	}

	public void setRollNo(int rollNo) {
		this.rollNo = rollNo;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
	public void display()
	{
		System.out.println("Student Roll No : "+getRollNo());
		System.out.println("Student Name : "+getName());
	}

	public static void main(String[] args) {
		Scanner sc =new Scanner(System.in);
		System.out.println("Enter the Roll number of a Student :");
		int n=sc.nextInt();
		System.out.println("Enter the name of a Student :");
		String name=sc.next();
                System.out.println();
                Student ob=new Student(); //calling non parameterized constructor
                System.out.println("------------------------------------");
		Student ob1=new Student(n,name); //calling parameterized constructor
		ob1.display(); //calling the method
	}

}

Output

[Nithy26]

StudentDriver.java

class Student{
    int rollno;
    String name;
    Student(){
        rollno = 10;
        String name = "Tony";
       
    }
    Student(int rollno){
        this.rollno = rollno;
        
    }
    Student(String name){
        this.name = name;
        
    }
    Student(int rollno, String name){
        this.rollno = rollno;
        this.name = name;
        
    }
    
    int getRollNo(){
        return this.rollno;
    }
    public void setRollNo(int rollno){
        this.rollno = rollno;
    }
    String getName() {
        return this.name;
    }
    public void setName(String name){   
        this.name = name;
    }
    void display(){
        System.out.println("RollNo: " + rollno);
        System.out.println("Name: " + name);
        }
}
public class StudentDriver{
    public static void main(String[] args){
    Student s1=new Student();
    Student s2=new Student(30);
    Student s3=new Student("Nancy");

    Student s4=new Student(10,"Steve");

    s1.display();
    s2.display();
    s3.display();
    s4.display();

   
    }
}

[abitha05]

Constructor

package constructdemo;
import java.util.Scanner;
class student{
    private int rollno;
    private String name;
    student(){ // non-parameterized constructor
          }
    student(int rollno){ //one parameterized constructor
        this.rollno=rollno;
    }
    student(String name){
        this.name=name;
    }
    student(int rollno, String name){ // two parameterized constructor
          this.rollno=rollno;
          this.name=name;
    }
    public int getRollno() {         // getter and setter
        return rollno; 
    }
    public String getName() {
        return name;
    }
    public void setRollno(int rollno) {
        this.rollno = rollno;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void display(){
        System.out.println("student details");
        System.out.println("rollno :"+rollno+"\n"+"name :"+name);
    }}
public class StudentDriver {
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        System.out.println("Non parameterized constructor...");
        student obj1=new student();
        System.out.println("Enter the name");
        obj1.setName(sc.nextLine());
        System.out.println("Enter the rollno");
        obj1.setRollno(sc.nextInt());
        obj1.display();
        System.out.println("Two parameteized constructor...");
        student obj2=new student(3,"abi");
        obj2.display();
        System.out.println("one parameterized constructor...");
        student obj3=new student("nisha");
        obj3.display();
        student obj4=new student(10);
        obj4.display();
 }
}

output:

[naveenkarthik-klu]

ConstructorsTask.java

class Student {
    private int rollNo;
    private String name;

    // defining constructors

    Student() {
        System.out.println("Non-Parameterized constructor is invoked");
    }

    Student(int rollNo) {
        System.out.println("Constructor with one parameter - roll number");
        this.rollNo = rollNo;
        System.out.println("Roll number: " + this.rollNo);
    }

    Student(String name) {
        System.out.println("Constructor with one parameter - name");
        this.name = name;
        System.out.println("Name: " + this.name);
    }

    Student(int rollNo, String name) {
        System.out.println("Constructor with two parameters");

    }

    // getters and setters method

    public int getRollNo() {
        return rollNo;
    }

    public void setRollNo(int rollNo) {
        this.rollNo = rollNo;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void display() {
        System.out.println("Display method:");
        System.out.println("Student name: " + getName());
        System.out.println("Roll number: " + getRollNo());
    }
}

public class ConstructorsTask {
    public static void main(String[] args) {
        Student s1 = new Student(); // non parameterized constructor is invoked
        Student s2 = new Student(4080); // parameterized constructor is invoked
        s2.setRollNo(4080);
        Student s3 = new Student("Naveen"); // parameterized constructor is invoked
        s3.setName("Naveen");
        Student s4 = new Student(4112, "Karthik"); // parameterized constructor is invoked
        String name = "naveen";
        int rollNo = 4109;
        s4.setName(name);
        s4.setRollNo(rollNo);
        s4.display();
    }
}

Output:

[Tamilarasi-palanisamy]

Student

class Student{
    private int rollNo;
    private String Name;
    
    public int getRollNo() {
        return rollNo;
    }
    public void setRollNo(int rollNo) {
        this.rollNo = rollNo;
    }
    public String getName() {
        return Name;
    }
    public void setName(String name) {
        Name = name;
    }
    Student(){}
    Student(int rollNo){
        this.rollNo = rollNo;
    }
    Student(String name){
        this.Name = name;
    }
    Student(int rollNo,String name){
        this.rollNo=rollNo;
        this.Name = name;
    }
    public void display(){
        System.out.println("Nameof the Student is:"+getName());
        System.out.println("RollNo of the Student is:"+getRollNo());
    }
}
public class StudentDriver{
    public static void main(String[] args){
        Student student1= new Student();
        student1.setName("tamil");
        student1.setRollNo(101);
        Student student2= new Student(301);
        Student student3= new Student("saratha");
        Student student4= new Student(201,"parkavi");
        student1.display();
        student2.display();
        student3.display();
        student4.display();
    }
}

Output:

[Sanjayee]

studnew.java

class student
{
    private int roll_no;
    private String name;
    public student() //user defined constructor with no parameters passed  
    {
    
    }
    public student(int roll_no)//Parameterized constructor for roll no
    {
        this.roll_no=roll_no;   
    }
    public student(String name)//Parameterized constructor for name
    {
        this.name=name;
    }
    public void setname(String name)//assigning name using set method
    {
        this.name=name;
    }
    public void setrollno(int roll_no) //assigning roll_no using set method
    {
        this.roll_no=roll_no;
    }
    public int getroll_no() // used to get the value of roll no
    {
        return roll_no;
    }
    public String getname() //used to get the value of name using getter method
    {
        return name;
    }
    public String Display() // Displays both name and roll no which has been passed from driver class and gets assigned in the current occurence
    {
        return "Name: "+name+"\nRollNo: "+roll_no;
    }

}
public class studnew {
    public static void main(String args[])
    {
        student s1=new student();//invokes user defined constructors with no parameters
        student s2=new student(26);//invokes user defined parameterized constructors with integer argument 
        student s3=new student("Sanjay");//invokes user defined parameterized constructors with String argument 
        System.out.println("Name: "+s2.getroll_no()+"\nRoll_no: "+s3.getname());
        s1.setname("Riyaz");//using setter to pass the value for name 
        s1.setrollno(27);//using setter to pass the value  for roll number
        System.out.println("Name: "+s1.getname()+"\nRoll no: "+s1.getroll_no());//getting value using getter method
        System.out.println(s1.Display());
    }    
}

Output

[RajkapoorR]

1

class Student{
  private int rollNo;
  private String name;
  
  Student(){
    System.out.println("No args constructor");
  }

  public Student(int rollNo) {
    this.rollNo = rollNo;
  }

  public Student(String name) {
    this.name = name;
  }

  public Student(int rollNo, String name) {
    this.rollNo = rollNo;
    this.name = name;
  }

  public int getRollNo() {
    return rollNo;
  }

  public void setRollNo(int rollNo) {
    this.rollNo = rollNo;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  @Override
  public String toString() {
    return "Student [name=" + name + ", rollNo=" + rollNo + "]";
  }
  
  public void display(){
    
    System.out.println("Student [name=" + name + ", rollNo=" + rollNo );
  }
  
  
}
public class StudentDriver{
  public static void main(String[] args) {
    Student s1 =new Student();
    s1.setName("Raj");
    s1.setRollNo(7777);
    Student s2 =new Student(77);
    Student s3 =new Student("Roshan");
    Student s4 =new Student(77,"Rajkapoor");
    System.out.println(s1);
    System.out.println(s2);
    System.out.println(s3);
    System.out.println(s4);

    
  }
}

[lakshmiparkav]

class Student{
    private int rollNo;
    private String Name;
    
    public int getRollNo() {
        return rollNo;
    }
    public void setRollNo(int rollNo) {
        this.rollNo = rollNo;
    }
    public String getName() {
        return Name;
    }
    public void setName(String name) {
        Name = name;
    }
    Student(){}
    Student(int rollNo){
        this.rollNo = rollNo;
    }
    Student(String name){
        this.Name = name;
    }
    Student(int rollNo,String name){
        this.rollNo=rollNo;
        this.Name = name;
    }
    public void display(){
        System.out.println("Name of the Student is:"+getName());
        System.out.println("RollNo of the Student is:"+getRollNo());
    }
}
public class StudentMain{
    public static void main(String[] args){
        Student student1= new Student();
        student1.setName("saratha");
        student1.setRollNo(1);
        Student student2= new Student(2);
        Student student3= new Student("parkavi");
        Student student4= new Student(3,"lakshmi");
        student1.display();
        student2.display();
        student3.display();
        student4.display();
    }
}

[sarathaselvam24]

class Student{

    int rollNo;
    String name;
    Student(){
    }
    
    Student(int rollNo){
        this.rollNo=rollNo;
        this.name = "Default";
    }
    Student(String name){
        this.name = name;
        this.rollNo=0;
    }
    Student(int rollNo,String name){
        this.rollNo = rollNo;
        this.name = name;
    }
    
    protected void display(){
        System.out.println("RollNo: "+this.rollNo);
        System.out.println("Name: "+this.name);
    }
    
     int getRollNo(){
        return this.rollNo;
    }
     String getName(){
        return this.name;
    }
     void setRollNo(int rollNo){
        this.rollNo=rollNo;
    }
     void setName(String name){
        this.name=name;
    }
    }
    
    public class MainClass {
    
    public static void main(String[] args) {
        
        Student s1=new Student(10,"saratha");
        Student s2=new Student(20);
        Student s3=new Student("selvam");
        Student s4=new Student();
    
        s1.display();
        System.out.println();
        s2.display();
        System.out.println();
        s3.display();
        System.out.println();
        s4.display();
        System.out.println();
        s2.setName("saranya");
        s3.setRollNo(339);
    
        s2.display();
        System.out.println();
        s3.display();
    }
    }

[Shalini-Venugopal]

class Student{

    int rollNo;
    String name;
    
    Student(){
        rollNo=110;
        String name="ABC";
    }
    
    Student(int rollNo){
        this.rollNo=rollNo;
        this.name = "Default";
    }
    
    Student(String name){
        this.name = name;
        this.rollNo=0;
    }
    
    Student(int rollNo,String name){
        this.rollNo = rollNo;
        this.name = name;
    }
    
    protected int getRollNo(){
        return this.rollNo;
    }
    
    protected String getName(){
        return this.name;
    }
    
    protected void setRollNo(int rollNo){
        this.rollNo=rollNo;
    }
    
    protected void setName(String name){
        this.name=name;
    }
    
    @Override
    public String toString() {
        return "Student [name=" + name + ", rollNo=" + rollNo + "]";
    }
}

public class Main {
    public static void main(String[] args) {
        
        Student s1=new Student(1, "Shalini");
        Student s2=new Student(2, "Kamini");
        Student s3=new Student("Stranger");
        Student s4=new Student();
        System.out.println(s1);
        System.out.println(s2);
        System.out.println(s3);
        System.out.println(s4);
    }
}

[premkumar-selvam]

class Student {
	private int rollNo;
	private String name;

	public Student() {
		super();
	}

	public Student(int rollNo) {
		super();
		this.rollNo = rollNo;
	}

	public Student(String name) {
		super();
		this.name = name;
	}

	public Student(int rollNo, String name) {
		super();
		this.rollNo = rollNo;
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getRollNo() {
		return rollNo;
	}

	public void setRollNo(int rollNo) {
		this.rollNo = rollNo;
	}

	public void display() {
		System.out.println("name: " + this.getName() + " roll no: " + this.getRollNo());
	}
}

public class StudentDetails {
	public static void main(String args[]) {
		Student studentOne = new Student();
		studentOne.display();
		Student studentTwo = new Student(12);
		studentTwo.display();
		Student studentThree = new Student("test");
		studentThree.display();
		Student studentFour = new Student(12, "testing");
		studentFour.display();
	}

}

[kadhalish]

class Student{
    private int rollno;
    private String name;
    public Student(int rollno, String name) {
        this.rollno = rollno;
        this.name = name;
    }
    
    public Student(int rollno) {
        this.rollno = rollno;
    }
    

    public Student(String name) {
        this.name = name;
    }
    public Student(){
        rollno=1;
        name="Kane";
    } 

    public int getRollno() {
        return rollno;
    }
    public void setRollno(int rollno) {
        this.rollno = rollno;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
   void display(){
    System.out.println("RollNo: " + rollno+" Name: " + name);
   }
}




public class StudentDriver {
    public static void main(String[] args) {
        Student student1=new Student(10,"Peter");
        Student student2=new Student(12);
        Student student3=new Student("Ram");
        System.out.println("Name of student 3 :");
        System.out.println(student3.getName());
        System.out.println("RollNo of student 2 :");
        System.out.println(student2.getRollno());
        System.out.println("Student 1 details");
        student1.display();

        
    }
}

[prasetha21-max]

// Student.java
public class Student {

    private int rollNo;
    private String name;

    public Student() {}

    public Student(int rollNo, String name) {
        this.rollNo = rollNo;
        this.name = name;
    }

    public int getRollNo() {
        return rollNo;
    }

    public void setRollNo(int rollNo) {
        this.rollNo = rollNo;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void display() {
        System.out.println("Roll no :" + this.rollNo + " and Name : " + this.name);
    }
}

// StudentDriver.java
public class StudentDriver {
    public static void main(String[] args) {
        Student student_1 = new Student();
        student_1.display();

        Student student_2 = new Student(1, "Ram");
        student_2.display();
    }
}

[Sdey0907]

Task 1 - Sayan Dey

class Student{
//fields and attribute
private int rollNo;
private String name;

//default constructor
public Student(){
    
}
//parameterized constructor
public Student(int rollNo,String name){
    this.rollNo = rollNo;
    this.name=name;
}
//getter and setter method
public int getRollNo(){
    return rollNo;
}
public void setRollNo(int rollNo){
    this.rollNo = rollNo;
}
public String getName(){
    return name;
}
public void setName(String name){
    this.name=name;
}
//display Student information
public void studentInformation(){
    System.out.println("Roll No :" +rollNo);
    System.out.println("Student Name :" +name);
}

}
class Main {
public static void main(String[] args) {
//create a student object
Student s1 = new Student();
//set the student attribute
s1.setRollNo(121);
s1.setName("Sayan Dey");

    //print the statement
    System.out.println("Roll No : " + s1.getRollNo());
    System.out.println( "Student Name : " + s1.getName());
}

}