Java 8 method references

Java 8 new features

The method referenced by the method name to point to a method.

The method of reference configuration can be made more compact and concise language to reduce redundant code.

Method references a pair of colons (: :).

Below, we define four methods Car class as an example, the distinction between Java supported four different methods reference.

public static class Car {
    public static Car create( final Supplier< Car > supplier ) {
        return supplier.get();
    }              
        
    public static void collide( final Car car ) {
        System.out.println( "Collided " + car.toString() );
    }
        
    public void follow( final Car another ) {
        System.out.println( "Following the " + another.toString() );
    }
        
    public void repair() {   
        System.out.println( "Repaired " + this.toString() );
    }
}

• Static method references: The syntax is Class :: static_method, examples are as follows:

  final Car car = Car.create( Car::new );
  final List< Car > cars = Arrays.asList( car );
  

• Any object method of a particular class Quote: It is Class :: method syntax examples are as follows:

  cars.forEach( Car::collide );
  

• Method references a specific object: it is instance :: method syntax examples are as follows:

  cars.forEach( Car::repair );
  

• Constructor Quote: The syntax is Class :: new, or more generally the Class <T> :: new examples are as follows:

  final Car police = Car.create( Car::new );
  cars.forEach( police::follow );
  

Method references instance of

In Java8Tester.java file enter the following code:

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

public class Java8Tester {
   public static void main(String args[]){
      List names = new ArrayList();
		
      names.add("Google");
      names.add("w3big");
      names.add("Taobao");
      names.add("Baidu");
      names.add("Sina");
		
      names.forEach(System.out::println);
   }
}

Example we will System.out :: println method as a static method to reference.

Implementation of the above script, output is:

$ javac Java8Tester.java 
$ java Java8Tester
Google
w3big
Taobao
Baidu
Sina

Java 8 new features