A class Admission numbers of 100 students . Some of the data members / member function are given below : 
Class name : admission 
Data members /Instance variable : 
Adno[]: Integer array to store admission numbers 
Member function /methods: 
Admission():constructor to initialize the array elements 
Voidfillarray():to accept the element of the array in ascending order 
Intbinsearch(int I,int u ,int v): to search for a particular admission number (v), using binary search and recursive technique and return 1 if found otherwise returns -1

Answers:

import java.util.*;

class Admission

{

 int Adno[]=new int[100];

 static Scanner sc = new Scanner(System.in);

 Admission() // Default constructor

 {

 for(int i=0; i<100; i++)

 {

 Adno[i]=0;

 }

 }

 void fillArray()throws Exception // Function to accept elements in ascending order

 {

 for(int i=0; i<100; i++)

 {

 System.out.print("Enter Admission no of student "+(i+1)+": ");

 Adno[i] = sc.nextInt();

 }

 /*Sorting the array in ascending order */

 int temp=0;

 for(int i=0; i<99; i++)

 {

 for(int j=i+1; j<100; j++)

 {

 if(Adno[i]>Adno[j])

 {

 temp = Adno[i];

 Adno[i] = Adno[j];

 Adno[j] = temp;

 }

 }

 }

 }

 int binSearch(int l, int u, int v) // Recursive function implementing binary search

 {

 int mid = (l + u)/2;

 if(u < l) // condition if the search is unsuccessful

 {

 return -1;

 }

 if(v==Adno[mid]) // condition if the search is successful

 {

 return 1;

 }

 else if(v>Adno[mid])

 {

 return binSearch(mid+1,u,v);

 }

 else

 {

 return binSearch(l,mid-1,v);

 }

 }

 public static void main(String args[])throws Exception

 {

 Admission ob = new Admission();

 System.out.println("Enter Admission number in ascending order");

 ob.fillArray();

 System.out.print("Enter an Admission number to search : ");

 int v = sc.nextInt();

 int f = ob.binSearch(0,99,v);

 System.out.println("*****************************");

 if(f == 1)

 {

 System.out.println("Admission Number found");

 }

 else

 {

 System.out.println("Admission Number Not found");

 }

 }

} 

Output: