Use Lambda instead of anonymous classes

Medium

---

Java

What is it?

The practice recommends using lambda expressions instead of anonymous classes, which can usually be identified when anonymous classes are implemented for interfaces with a single abstract method.

Why apply it?

Using lambdas simplifies the code by making it more concise and readable, and leverages functional programming patterns which are advantageous in terms of performance and maintainability.

How to fix it?

Replace the anonymous class implementation with an equivalent lambda expression where applicable.

Read more:

https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html

Examples

Example 1:

Positive

Correct implementation following the practice.

package org.example;

import java.util.ArrayList;
import java.util.List;

//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
public class Main {

    private void ListInitialisation() {
        List<Integer> list = new ArrayList<>(100);
    }


    private void useLambda() {
        
        new Thread(() -> System.out.println("Hello, World!")).start();

    }
    
}

Negative

Incorrect implementation that violates the practice.

package org.example;

import java.util.ArrayList;
import java.util.List;

//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
public class Main {

    private void ListInitialisation() {
        List<Integer> list = new ArrayList<>(100);
    }


    private void useLambda() {

        new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println("Hello, World!");
            }
        }).start();

    }
    
}