Simple example showing usage of Streams API

StreamMain.java

package com.cavok.stream;

import lombok.AllArgsConstructor;
import lombok.Getter;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * Created by dennis on 13/11/2016.
 */
public class StreamMain
{
    public static void main(String[] args)
    {
        BasicStreamOperations basicStreamOperations = new BasicStreamOperations();
        List<SomeSimpleObject> inputList = Arrays.asList(new SomeSimpleObject("One", 1, Arrays.asList("Second", "Third")),
                                                         new SomeSimpleObject("Two", 2, Arrays.asList("First", "Third")), 
                                                         new SomeSimpleObject("Three", 3, Arrays.asList("First","Second")));
        
        basicStreamOperations.extractElementProperty(inputList).forEach(s -> System.out.println(s));

        basicStreamOperations.extractSubList(inputList).forEach(s -> System.out.println(s));

        basicStreamOperations.extractMapOfProperties(inputList).
                forEach((k, v) -> System.out.println(String.format("Map Entry\n %s: %s", k, v.stream().
                                                                   reduce((s1, s2) -> s1 + ", " + s2).map(r -> r).
                                                                   orElse("Value absent"))));

        basicStreamOperations.extractMapOfSelf(inputList).
                forEach((k, v) -> System.out.println(String.format("Map Entry\n %s: %s, %d, list: [%s]", k, v.getName
                        (), v.getValue(), v.getOthers().stream().reduce((s1, s2) -> s1 + ", " + s2).map(r -> r)
                                           .orElse("Value absent"))));
    }
}

class BasicStreamOperations
{
    public List<String> extractElementProperty(List<SomeSimpleObject> inputList)
    {
        return inputList.stream().map(c -> c.getName()).collect(Collectors.toList());
    }

    public List<String> extractSubList(List<SomeSimpleObject> inputList)
    {
        return inputList.stream().flatMap(c -> c.getOthers().stream()).collect(Collectors.toList());
    }

    public Map<String, List<String>> extractMapOfProperties(List<SomeSimpleObject> inputList)
    {
        return inputList.stream().collect(Collectors.toMap(SomeSimpleObject::getName, SomeSimpleObject::getOthers));
    }

    public Map<String, SomeSimpleObject> extractMapOfSelf(List<SomeSimpleObject> inputList)
    {
        return inputList.stream().collect(Collectors.toMap(SomeSimpleObject::getName, c -> c));
    }
}

@AllArgsConstructor
class SomeSimpleObject
{
    @Getter
    private String name;
    @Getter
    private int value;
    @Getter
    private List<String> others;
}