Multiple inheritance using interfaces in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an interface named Printable.

Java

public interface [1] {
    void print();
}

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APrint

BPrintable

CPrinter

DPrintInterface

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name instead of interface name.

Misspelling the interface name.

The interface name must be Printable as declared.

2fill in blank

medium

Complete the code to declare a class Document that implements Printable interface.

Java

public class Document implements [1] {
    public void print() {
        System.out.println("Printing document");
    }
}

Drag options to blanks, or click blank then click option'

APrintable

BPrinter

CPrint

DPrintableInterface

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name instead of interface name in implements.

Misspelling the interface name.

The class must implement the interface named Printable.

3fill in blank

hard

Fix the error in the class declaration to implement two interfaces: Printable and Showable.

Java

public class Report implements [1] {
    public void print() {
        System.out.println("Printing report");
    }
    public void show() {
        System.out.println("Showing report");
    }
}

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APrintable, Showable

BPrintable & Showable

CPrintable Showable

DPrintable | Showable

Attempts:

3 left

💡 Hint

Common Mistakes

Using & or | instead of commas.

Omitting commas between interface names.

Multiple interfaces are separated by commas in the implements clause.

4fill in blank

hard

Fill both blanks to complete the interface declarations and class implementing both.

Java

interface [1] {
    void print();
}
interface [2] {
    void show();
}
class Presentation implements Printable, Showable {
    public void print() {
        System.out.println("Print slide");
    }
    public void show() {
        System.out.println("Show slide");
    }
}

Drag options to blanks, or click blank then click option'

APrintable

BPrintableInterface

CShowable

DShowInterface

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatch between interface names and class implements clause.

Using different names for interfaces.

The interfaces are named Printable and Showable as used in the class.

5fill in blank

hard

Fill all three blanks to complete the code that uses multiple inheritance with interfaces and calls their methods.

Java

interface [1] {
    void print();
}
interface [2] {
    void show();
}
class Report implements Printable, Showable {
    public void print() {
        System.out.println("Printing report");
    }
    public void show() {
        System.out.println("Showing report");
    }
}
public class Main {
    public static void main(String[] args) {
        [3] obj = new Report();
        obj.print();
        obj.show();
    }
}

Drag options to blanks, or click blank then click option'

APrintable

BShowable

CReport

DPrintableShowable

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent interface name for the variable type.

Using interface names instead of class name for the object.

The interfaces are Printable and Showable, and the variable type is the class Report.