public class chapt9Tester the tester is complete just run

public class chapt9Tester {                 // the tester is complete, just run it after you finish the rest of the code

     public static void main(String[] args) {

           // create two bankaccount objects a1 using constructor without parameters, and object a2 using constructor with parameter sending it the amount 2000.50

           BankAccount a1 = new BankAccount();

           BankAccount a2 = new BankAccount(2000.50);

           // create two coin objects c1 using constructor without parameters and c2 using constructor and sending 0.25 and \"Quarter\"

           Coin c1 = new Coin();

           Coin c2 = new Coin(0.25, \"Quarter\");

           // now create an array of 4 elements of type Measurable and load it with the 4 objects that you just created

           Measurable marr[] = { a1, a2, c1, c2 };

           for ( int i=0; i< marr.length; i++) {

                double r = marr[i].getMeasure(); // getMeasure() will behave differently depending on the object that called it

                System.out.println(\"Return \" + r);

           }

                // notice that a variable of type Measure marr can refer to BankAccount object or Coin object without casting.

                // however it can only call the methods that are declared in the Measure interface

     }

}

// This is the Interface complete the missing code, (if you use Eclipse: click on File -> New -> Interface )

public _______________ Measurable {

        double getMeasure();

}

// BankAccount class will use the interface

public class BankAccount ___________________ Measurable{

     private double balance;

     public BankAccount(double amt) {           //constructor with parameter

           balance = amt;

     }

     public BankAccount() {                //constructor without parameter, set balance to 0

           ____________________

     }

     public void deposit(double amt){

           balance = balance + amt;

     }

     public void withdraw(double amt){

           balance = balance - amt;

     }

     @Override

     public double getMeasure() {    

           return balance;

     }

}

// Coin class will use the same interface

public class Coin ________________   ____________________ {

     private double value = 1;

     private String name = \"Dollar\";

     public Coin(double v, String n){      // constructor with two parameters

           value = v;

           name = n;

     }

     public _______________ {         // constructor without parameters

value = 1;

           _____________________;

     }

    

     // implement the interface method getMeasure here

     public _________   ___________________ {

           return value;

     }

}

--------------------------------------------------------------------------

Solution

// Measurable.java interface
public interface Measurable {
double getMeasure();
}

// BankAccount.java BankAccount class will use the interface
public class BankAccount implements Measurable{
private double balance;
public BankAccount(double amt) {   
//constructor with parameter
balance = amt;
}
public BankAccount() {
//constructor without parameter, set balance to 0
balance = 0.0;
}
public void deposit(double amt){
balance = balance + amt;
}
public void withdraw(double amt){
balance = balance - amt;
}
@Override
public double getMeasure() {
return balance;
}
}

// Coin.java, Coin class will use the same interface
public class Coin implements Measurable {
private double value = 1;
private String name = \"Dollar\";
public Coin(double v, String n){
// constructor with two parameters
value = v;
name = n;
}
public Coin() {   
// constructor without parameters
value = 1;
name = \"NULL\";
}
  
// implement the interface method getMeasure here
public double getMeasure() {
return value;
}
}

// chapt9Tester.java
public class chapt9Tester {   
// the tester is complete, just run it after you finish the rest of the code
public static void main(String[] args) {
// create two bankaccount objects a1 using constructor without parameters, and object a2 using constructor with parameter sending it the amount 2000.50
BankAccount a1 = new BankAccount();
BankAccount a2 = new BankAccount(2000.50);
// create two coin objects c1 using constructor without parameters and c2 using constructor and sending 0.25 and \"Quarter\"
Coin c1 = new Coin();
Coin c2 = new Coin(0.25, \"Quarter\");
// now create an array of 4 elements of type Measurable and load it with the 4 objects that you just created
Measurable marr[] = { a1, a2, c1, c2 };
for ( int i=0; i< marr.length; i++) {
double r = marr[i].getMeasure();
// getMeasure() will behave differently depending on the object that called it
System.out.println(\"Return \" + r);
}
}

}

/*
output:

Return 0.0
Return 2000.5
Return 1.0
Return 0.25

*/