Java code to illustrate package and Interface. Here screenshot shows two packages -First and second. Package First contains Interface myinterface.(myinterface.java) Package second contains Class Banking(Banking.java) myinterface.class package First; public interface myinterface { public void createAccount(int v); public void displayBalance(); public void displayRecords(); public void updateBalance(int val); } Banking.java package second; import java.util.Scanner; import First.myinterface; public class Banking implements myinterface{ static int no; int account_no; int balance; String Cust_name; void getdata() { System.out.println("Enter Balance"); Scanner sc=new Scanner(System.in); balance=sc.nextInt(); System.out.println("Enter Customer Name"); Cust_name=sc.next(); } public void createAccount(int val) { account_no=val; getdata(); } int getAccno() { return account_no; } public void displayB...