This is a complete java program for bank management system.

Program

import java.io.*;

class BankWork {
  // initialize and declare objects.
  final int max_limit = 20;
  final int min_limit = 1;
  final double min_bal = 500;

  private String name[] = new String[20];
  private int accNo[] = new int[20];
  private String accType[] = new String[20];
  private double balamount[] = new double[20];

  static int totRec = 0;

  // create a constructor here of Bank.
  BankWork() {
    for (int i = 0; i < max_limit; i++) {
      name[i] = "";
      accNo[i] = 0;
      accType[i] = "";
      balamount[i] = 0.0;
    }
  }

  // Create method to create New entry.
  public void newEntry() {
    String str;

    int account;
    double amount;
    boolean permit;
    permit = true;

    if (totRec > max_limit) {
      System.out.println("\n\n\nSorry we cannot admit you in our bank...\n\n\n");
      permit = false;
    }

    // create new entry.
    if (permit = true) {
      totRec++;

      // Incrementing Records               
      System.out.println("\n\n\n=====SAVING NEW ENTRY=====");
      try {
        accNo[totRec] = totRec; //Created  AutoNumber  to accNo so no invalid id occurs
        System.out.println("Account Number :  " + accNo[totRec]);

        // create object.
        BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));

        // enter the name of customer here.
        System.out.print("Enter the name of the Customer : ");
        System.out.flush();

        name[totRec] = obj.readLine();

        // enter the type of account.
        System.out.print("Enter Account Type : ");
        System.out.flush();

        accType[totRec] = obj.readLine();
        do {
          // enter the starting amount.
          // minimum amount must be 1000.
          System.out.print("Enter Initial  Amount to be deposited : ");
          System.out.flush();
          str = obj.readLine();

          balamount[totRec] = Double.parseDouble(str);
        }
        while (balamount[totRec] < min_bal);

        System.out.println("\n\n\n");
      } catch (Exception e) {
        System.out.println("Exception in Entering a record.....");
      }
    }
  }

  // create method to display records.
  public void display() {
    String str;
    int account = 0;
    boolean valid = true;

    System.out.println("\n\n=====DISPLAYING THE RECORDS=====\n");
    try {
      // create object.
      BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));

      // enter account number.
      System.out.print("Enter the account number for display record : ");
      System.out.flush();

      str = obj.readLine();
      account = Integer.parseInt(str);

      // check for valid account number
      if (account < min_limit || account > totRec) {
        System.out.println("\n\n\nInvalid Account Number \n\n");
        valid = false;
      }

      if (valid == true) {
        System.out.println("\n\nAccount Number : " + accNo[account]);
        System.out.println("Name : " + name[account]);
        System.out.println("Account Type : " + accType[account]);
        System.out.println("Balance Amount : " + balamount[account] + "\n\n\n");
      }
    } catch (Exception e) {
      System.out.println("Exception in Displaying record.....");
    }
  }

  // create method to deposit amount.
  public void deposit() {
    String str;
    double amount;
    int account;
    boolean valid = true;
    System.out.println("\n\n\n=====DEPOSIT AMOUNT=====");

    try {
      // create object.
      BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));

      System.out.print("Enter Account No : ");
      System.out.flush();

      str = obj.readLine();
      account = Integer.parseInt(str);

      // check valid account number.
      if (account < min_limit || account > totRec) {
        System.out.println("\n\n\nInvalid Account Number \n\n");
        valid = false;
      }

      if (valid == true) {
        System.out.print("Enter Amount you want to Deposit  : ");
        System.out.flush();

        str = obj.readLine();
        amount = Double.parseDouble(str);

        balamount[account] = balamount[account] + amount;

        //Displaying Depsit Details
        System.out.println("\nAfter Updation...");
        System.out.println("Account Number :  " + account);
        System.out.println("Balance Amount :  " + balamount[account] + "\n\n\n");
      }
    } catch (Exception e) {
      System.out.println("Exception in Depositing record.....");
    }
  }

  // creating method for withdraw money.
  public void withdraw() {
    String str;

    double amount, checkamount;
    int account;
    boolean valid = true;

    System.out.println("\n\n\n=====WITHDRAW MONEY=====");
    try {
      // create object. 
      BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));

      // enter account number for entering money
      System.out.print("Enter the account number to deposit money : ");
      System.out.flush();

      str = obj.readLine();
      account = Integer.parseInt(str);

      // check for valid account number.
      if (account < min_limit || account > totRec) {
        System.out.println("\n\n\nInvalid Account Number \n\n");
        valid = false;
      }

      if (valid == true) {
        System.out.println("Balance is : " + balamount[account]);
        System.out.print("Enter Amount you want to withdraw  : ");
        System.out.flush();

        str = obj.readLine();
        amount = Double.parseDouble(str);
        checkamount = balamount[account] - amount;

        if (checkamount >= min_bal) {
          balamount[account] = checkamount;

          // Updating the amount after withdraw.
          System.out.println("\nAfter Updation...");
          System.out.println("Account Number :  " + account);
          System.out.println("Balance Amount :  " + balamount[account] + "\n\n\n");
        } else {
          System.out.println("\n\nAs per Bank Rule you should maintain minimum balance of Rs 500\n\n\n");
        }
      }
    } catch (Exception e) {
      System.out.println("Exception in Withdrawing record.....");
    }
  }
};

public class Main {
  public static void main(String args[]) {
    String str;
    int choice;
    choice = 0;

    BankWork BW_obj = new BankWork();

    do {
      // creating Menu.
      System.out.println("Choose Your Choices ...");
      System.out.println("1) New Record Entry ");
      System.out.println("2) Display Record Details ");
      System.out.println("3) Deposit...");
      System.out.println("4) Withdraw...");
      System.out.println("5) Exit");
      System.out.print("Enter your choice :  ");
      System.out.flush();
      try {
        // creating objects.
        BufferedReader obj = new BufferedReader(new InputStreamReader(System.in));
        str = obj.readLine();
        choice = Integer.parseInt(str);

        switch (choice) {
        case 1:
          // for new entry.
          BW_obj.newEntry();
          break;

        case 2:
          // for display.
          BW_obj.display();
          break;

        case 3:
          // for deposit.
          BW_obj.deposit();
          break;

        case 4:
          // for display.
          BW_obj.withdraw();
          break;

        case 5:
          System.out.println("\n\n.....THANKS FOR VISITING.....");
          break;

        default:
          System.out.println("\nInvalid Choice \n\n");
        }
      } catch (Exception e) {
        System.out.println("Exception in Main....");
      }
    }
    while (choice != 5);
  }
}

Output

Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  1



=====SAVING NEW ENTRY=====
Account Number :  1
Enter the name of the Customer : Aditya
Enter Account Type : Saving
Enter Initial  Amount to be deposited : 1500




Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  2


=====DISPLAYING THE RECORDS=====

Enter the account number for display record : 1


Account Number : 1
Name : Aditya
Account Type : Saving
Balance Amount : 1500.0



Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  3



=====DEPOSIT AMOUNT=====
Enter Account No : 1
Enter Amount you want to Deposit  : 2500

After Updation...
Account Number :  1
Balance Amount :  4000.0



Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  2


=====DISPLAYING THE RECORDS=====

Enter the account number for display record : 1


Account Number : 1
Name : Aditya
Account Type : Saving
Balance Amount : 4000.0



Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  4



=====WITHDRAW MONEY=====
Enter the account number to deposit money : 1
Balance is : 4000.0
Enter Amount you want to withdraw  : 2000

After Updation...
Account Number :  1
Balance Amount :  2000.0



Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  2


=====DISPLAYING THE RECORDS=====

Enter the account number for display record : 1


Account Number : 1
Name : Aditya
Account Type : Saving
Balance Amount : 2000.0



Choose Your Choices ...
1) New Record Entry 
2) Display Record Details 
3) Deposit...
4) Withdraw...
5) Exit
Enter your choice :  5


.....THANKS FOR VISITING.....