Fun With Lambda in jdk8

FunWithLambda.java

import org.junit.Test;

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

import static com.google.common.collect.FluentIterable.from;
import static java.util.Arrays.asList;
import static java.util.streams.Streams.stream;
import static org.fest.assertions.Assertions.assertThat;

public class FunWithLambda {

	@Test
	public void shouldFilterASimpleCollection() {
		List<String> stringsAsList = asList("foo", "bar", "qix", "baz");
		ArrayList<String> resultList = stream(stringsAsList).filter(x -> x.startsWith("b")).into(new ArrayList<String>());
		assertThat(resultList).containsOnly("bar", "baz");
	}

	@Test
	public void shouldFilterASimpleCollectionWithoutStupidStreams() {
		List<String> stringsAsList = asList("foo", "bar", "qix", "baz");
		List<String> resultsLists = stringsAsList.stream().filter(x -> x.startsWith("b")).into(new ArrayList<String>());
		assertThat(resultsLists).containsOnly("bar", "baz");
	}

	@Test
	public void shouldFilterWithGuava() {
		List<String> stringsAsList = asList("foo", "bar", "qix", "baz");
		Iterable<String> resultsLists = from(stringsAsList).filter(x -> x.startsWith("b"));
		assertThat(resultsLists).containsOnly("bar", "baz");
	}

	@Test
	public void shouldReduceASimpleCollection() {
		List<Integer> stringsAsList = asList(1, 2, 3, 4, 5);
		Integer sum = stream(stringsAsList).reduce((x, y) -> x + y).get();
		assertThat(sum).isEqualTo(15);
	}

}

You need a jdk8, with guava & fest assert to run the code.