Java class definition create Bank class

// basic OOP syntax
class BankAccount {
   private double balance; // account balance

   public BankAccount(double openingBalance) // constructor
   {/*from   ww  w . java 2 s.c  o m*/
      balance = openingBalance;
   }

   public void deposit(double amount) // makes deposit
   {
      balance = balance + amount;
   }

   public void withdraw(double amount) // makes withdrawal
   {
      balance = balance - amount;
   }

   public void display() // displays balance
   {
      System.out.println("balance=" + balance);
   }
}

public class Main {
   public static void main(String[] args) {
      BankAccount ba1 = new BankAccount(100.00); 

      System.out.print("Before transactions, ");
      ba1.display(); 

      ba1.deposit(74.35); // make deposit
      ba1.withdraw(20.00); // make withdrawal

      System.out.print("After transactions, ");
      ba1.display(); 
   }
}