Untitled

import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Filters;
import com.mongodb.client.model.Updates;
import java.util.Iterator;
import java.util.Scanner;
import org.bson.Document;

public class App{

  public static void main(String args[]) {
    try {
      Scanner sc = new Scanner(System.in);
      int studentID = 0, UG_POYear = 0;
      String fName = "", lName = "", UG_Dept = "", curr_city = "", email = "";
      MongoClient mongo = new MongoClient("mongodb+srv://rohandoshi21:rohandoshi21@cluster0.fw2cxxf.mongodb.net/?retryWrites=true&w=majority");
      System.out.println("\n\t Connected to the database successfully...!!");
      MongoDatabase database = mongo.getDatabase("assignment_no_12");
      MongoCollection<Document> collection = database.getCollection("Student");
      System.out.println("\n\t Collection Student selected successfully...!!");
      int choice;
      while (true) {
        System.out.println(
          "\n\t === Main Menu === \n\t\t 1. Insert Data" +
          "\n\t\t 2. Display Data" +
          "\n\t\t 3. Update Document" +
          "\n\t\t 4. Delete Document" +
          "\n\t\t 5. Drop Collection" +
          "\n\t\t 6. Exit"
        );
        System.out.print("\n\t Enter Choice : ");
        choice = sc.nextInt();
        switch (choice) {
          case 1:
            System.out.print("\n\t Enter the ID of Student : ");
            studentID = sc.nextInt();
            System.out.print("\n\t Enter the First Name of Student : ");
            fName = sc.next();
            System.out.print("\n\t Enter the Last Name of Student : ");
            lName = sc.next();
            System.out.print("\n\t Enter the UG_POYear of Student : ");
            UG_POYear = sc.nextInt();
            System.out.print("\n\t Enter the UG_Dept of Student : ");
            UG_Dept = sc.next();
            System.out.print("\n\t Enter the curr_city of Student : ");
            curr_city = sc.next();
            System.out.print("\n\t Enter the email of Student : ");
            email = sc.next();
            Document document = new Document("_id", studentID)
              .append("fName", fName)
              .append("lName", lName)
              .append("UG_POYear", UG_POYear)
              .append("UG_Dept", UG_Dept)
              .append("curr_city", curr_city)
              .append("email", email);
            collection.insertOne(document);
            System.out.println("\n\t Document Inserted Successfully...!! \n");
            break;
          case 2:
            FindIterable<Document> iterDoc = collection.find();
            Iterator<Document> it = iterDoc.iterator();
            while (it.hasNext()) {
              System.out.println(it.next());
            }
            break;
          case 3:
            int ch = 0;
            System.out.print("\n\t Enter ID of student to update Data : ");
            studentID = sc.nextInt();
            System.out.print(
              "\n\t\t == UPDATE == \n\t\t\t 1. fName" +
              "\n\t\t\t 2. lName \n\t\t\t 3. UG_POYear" +
              "\n\t\t\t 4. UG_Dept \n\t\t\t 5. curr_city" +
              "\n\t\t\t 6. email \n\t\t\t 7. Cancel" +
              "\n\t\t Enter Choice = "
            );
            ch = sc.nextInt();
            if (ch == 1) {
              System.out.print("\n\t Enter new First name of student : ");
              fName = sc.next();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("fName", fName)
              );
              System.out.println("\n\t Document Updated Successfully...!!\n");
            } else if (ch == 2) {
              System.out.print("\n\t Enter new Last name of student : ");
              lName = sc.next();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("lName", lName)
              );
              System.out.println("\n\t Document Updated Successfully...!!\n");
            } else if (ch == 3) {
              System.out.print("\n\t Enter new UG PassOut Year of student :");
              UG_POYear = sc.nextInt();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("UG_POYear", UG_POYear)
              );
              System.out.println("\n\t Document Updated Successfully...!!\n");
            } else if (ch == 4) {
              System.out.print("\n\t Enter new UG Department of student :");
              UG_Dept = sc.next();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("UG_Dept", UG_Dept)
              );
              System.out.println("\n\t Document Updated Successfully...!!\n");
            } else if (ch == 5) {
              System.out.print("\n\t Enter new Current City of student : ");
              curr_city = sc.next();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("curr_city", curr_city)
              );
              System.out.println("\n\t Document Updated Successfully...!!\n");
            } else if (ch == 6) {
              System.out.print("\n\t Enter new email of student : ");
              email = sc.next();
              collection.updateOne(
                Filters.eq("_id", studentID),
                Updates.set("email", email)
              );
              System.out.println("\n\t Document Updated Successfully...!!");
            } else if (ch == 7) {
              System.out.println("\n\t Operation Cancelled Successfully...!!");
              break;
            } else {
              System.out.println("\n\t Invalid Choice...!!! \n");
              break;
            }
            break;
          case 4:
            System.out.print("\n\t Enter ID of student to delete Data : ");
            studentID = sc.nextInt();
            collection.deleteOne(Filters.eq("_id", studentID));
            System.out.println("\n\t Document Deleted Successfully...!!\n");
            break;
          case 5:
            collection.drop();
            System.out.println("\n\t\t\t\t ___ Thank You ..! __ \n");
            sc.close();
            mongo.close();
            System.exit(0);
            break;
          case 6:
            System.out.println("\n\t\t\t\t ___ Thank You ..! __ \n");
            sc.close();
            mongo.close();
            System.exit(0);
          default:
            System.out.println("\n\t Invalid Choice...!!! \n");
            break;
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}