Validate Student record with Custom exception

Q. Create a class Student with attributes roll no, name, age and course. Initialize values through parameterized constructor. If age of student is not in between 15 and 21 then generate user-defined exception "AgeNotWithinRangeException". If name contains numbers or special symbols raise exception "NameNotValidException". Define the two exception classes.

Answer:

Student class with the parameterized constructor to initialize the student record. If the inserted record is not valid, it generates user defined exception.

AgeNotWithInRangeException.java

class AgeNotWithInRangeException extends Exception
{
     public String toString()
     {
          return ("Age is not between 15 and 21. please ReEnter the Age");
     }
}


NameNotValidException.java

class NameNotValidException extends Exception
{
     public String validname()
     {
          return ("Name is not Valid..Please ReEnter the Name");
     }
}


Student.java

class Student
{
     int roll,age;
     String name,course;
     Student()
     {
          roll=0;
          name=null;
          age=0;
          course=null;
     }
     Student(int r,String n,int a,String c)
     {
          roll=r;
          course=c;
          int l,temp=0;
          l = n.length();
          for(int i=0;i<l;i++)
          {
               char ch;
               ch=n.charAt(i);
               if(ch<'A' || ch>'Z' && ch<'a' || ch>'z')
                    temp=1;
          }
          /*———-Checking Name——————–*/
          try
          {
               if(temp==1)
                    throw new NameNotValidException();
               else
                    name=n;
          }
          catch(NameNotValidException e2)
          {
               System.out.println(e2);
          }
          /*———-Checking Age——————–*/
          try
          {
               if(a>=15 && a<=21)
                    age=a;
               else
                    throw new AgeNotWithInRangeException();
          }
          catch(AgeNotWithInRangeException e1)
          {
               System.out.println(e1);
          }
     }
     void display()
     {
          System.out.println("roll Name Age Course");
          System.out.println("---------------------");
          System.out.println(roll+" "+name+" "+age+" " +course);
     }
}


StudentDemo.java

import java.io.*;
class StudentDemo
{
     public static void main(String args[])throws IOException
     {
          BufferedReader br=new BufferedReader(new InputStreamReader(System.in));

          System.out.print("Enter roll number: ");
          int roll = Integer.parseInt(br.readLine());
          System.out.print("\nEnter name: ");
          String name = br.readLine();
          System.out.print("\nEnter age: ");
          int age = Integer.parseInt(br.readLine());
          System.out.print("\nEnter course: ");
          String course = br.readLine();
          Student s = new Student(roll,name,age,course);
          s.display();
     }
}


Output:

i. When we enter invalid name or age

custom exception

ii. Enter valid name as well as age

custom exception
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