JAVA EE: What is Constructor reference | Method reference in Java 8

Tuesday 27 June 2017

What is Constructor reference | Method reference in Java 8 | Java method reference

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What is Constructor reference | Method reference in Java 8 | Java method reference

LambdaDemo.java

@FunctionalInterface
interface Message
{
    String displayMessage(char[] chArray);
}

public class LambdaDemo
{
    public static void main(String[] args)
    {

        /*
         * Note that, in this program strFunc() of FunctionalInterface
         * returns a reference of type String. In this program, the
         * expression "String::new" creates a constructor reference to
         * the String's constructor.
         */
        Message message = String::new;

        char[] charArray =  { 'P', 'e', 't', 'e', 'r' };

        /*
         * Here the method StrFunc() takes a Character array as an
         * argument, so the parameterized constructor 
         * String(char[] charArray) is referred here.
         * 
         * So finally, when ever you call the method strFunc() on
         * FunctionalInterface reference, a String object is
         * constructed and returned.
         */
        System.out.println(message.displayMessage(charArray));
    }

}