viveknaskar

package com.viveknaskar;

public class LambdaExample {

    public static void main(String[] args) {
        WishingInterface wishing = () -> {
            return "Hello World!";
        };
        System.out.println(wishing.wish());
    }

viveknaskar

package com.viveknaskar;

public class FunctionalInterfaceExampleBeforeJava8 {

    public static void main(String[] args) {

        // Creating anonymous inner class object
        new Thread(new Runnable() {
            @Override
            public void run() {

viveknaskar

package com.viveknaskar;

public class FunctionalInterfaceExampleAfterJava8 {

    public static void main(String[] args) {

        // lambda expressions to create object
        new Thread(() -> {
            System.out.println("Functional Interface After to Java 8");
        }).start();

viveknaskar

package com.viveknaskar;

// Class implementing the interface
public class DefaultMethodExample implements DefaultMethodInterface {

    @Override
    public void abstractMethod() {
        System.out.println("Hello from abstract method");
    }

viveknaskar

package com.viveknaskar;

public class StaticMethodExample implements StaticMethodInterface {
    // implementing abstract method
    public void existingMethod(String str) {
        System.out.println("String is: "+str);
    }
    public static void main(String[] args) {
        StaticMethodExample obj = new StaticMethodExample();

viveknaskar

package com.viveknaskar;

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

public class CountingCollections {

    public static void main(String[] args) {

        List<String> list = new ArrayList<>();

viveknaskar

package com.viveknaskar;

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

public class CountingCollectionsUsingStreams {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("Bruce");
        list.add("Tony");

viveknaskar

package com.viveknaskar;

import java.util.Optional;

public class ExampleWithOptional {
    public static void main(String[] args) {
        String[] cities = new String[10];
        /**
         * Using Optional class, we are doing a null check at cities[5]
         */

viveknaskar

package com.viveknaskar;

public class ExampleWithoutOptional {

    public static void main(String[] args) {

        String[] cities = new String[10];
        /**
         *  The array is empty is empty.
         *  No null check has been done, it will throw NullPointerException

viveknaskar

public static void main(String[] args) {
    /**
     * Constructed StorageToRedisOptions object using the method PipelineOptionsFactory.fromArgs to read options from command-line
     */
    StorageToRedisOptions options = PipelineOptionsFactory.fromArgs(args)
            .withValidation()
            .as(StorageToRedisOptions.class);

    Pipeline p = Pipeline.create(options);
    p.apply("Reading Lines...", TextIO.read().from(options.getInputFile()))