Solution: Constructors

 1 public class Account {
 2     private static int cntAcoountNo = 400000;  // static variable, class-wide usable
 3 
 4     private int accountNumber;
 5     private double balance;
 6 
 7     Account(double initialCredit) {             // Definition of parameterized constructor
 8         accountNumber = ++cntAcoountNo;
 9         balance = initialCredit;
10     }
11     public int getAccountNumber() {
12         return accountNumber;
13     }
14     public double getBalance() {
15         return balance;
16     }
17 }

 1 public class Main {
 2     public static void main(String[] args) {
 3         Account account1 = new Account(50);   // Creation of objects of the class Account
 4         Account account2 = new Account(100);  // using paramized constructor
 5         Account account3 = new Account(0);
 6 
 7         System.out.println("Account No.: " + account1.getAccountNumber() + "\tBalance: " + account1.getBalance());
 8         System.out.println("Account No.: " + account2.getAccountNumber() + "\tBalance: " + account2.getBalance());
 9         System.out.println("Account No.: " + account3.getAccountNumber() + "\tBalance: " + account3.getBalance());
10     }
11 }