Java Anonymous Class Implementing an Interface Example
Anonymous Class Exercise:
Write a Java program to create an interface called Greeting with a method sayHello(). In the main method, create an anonymous class that implements the Greeting interface and override the sayHello() method to print "Hello, World!". Call the sayHello() method.
Sample Solution:
Java Code:
Main.java
// Main class containing the main method
public class Main {
public static void main(String[] args) {
// Creating an anonymous class that implements the Greeting interface
Greeting greeting = new Greeting() {
@Override
public void sayHello() {
// Overriding the sayHello method to print "Hello, World!"
System.out.println("Hello, World!");
}
};
// Calling the sayHello method of the anonymous class
greeting.sayHello();
}
}
Output:
Hello, World!
Explanation:
- Interface Greeting: Defines a method sayHello() that must be implemented by any class that implements this interface.
- Main class: Contains the main method where the execution starts.
- Anonymous class: Implements the Greeting interface and overrides the sayHello() method to print "Hello, World!".
- Override sayHello(): Provides the implementation for the sayHello() method defined in the Greeting interface.
- Calling sayHello(): The overridden method is called to print the greeting message.
Note on Java Nested Classes:
- In this exercise, the Java nested classes concept is demonstrated through the use of an anonymous class.
- An anonymous class is a class without a name and is used to instantiate objects with certain modifications, such as implementing an interface or extending another class.
- This allows for concise and flexible code, particularly useful for implementing simple interfaces or abstract classes without cluttering the code with additional class definitions.
- The example shows how to implement the Greeting interface using an anonymous class.
- The anonymous class provides an implementation for the sayHello() method.
- The sayHello() method is invoked to display a greeting message.
Java Code Editor:
Improve this sample solution and post your code through Disqus.
Java Static Members Previous: Java Program with Local Class in Method - Car and Engine.
Java Static Members Next: Java Inner Class Accessing Outer Class Members Example.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
- Weekly Trends and Language Statistics
- Weekly Trends and Language Statistics