Java 8 example: two String arrays to one Set with Streams

Just an example

@Test
public void testArraysToStream() {
    String[] s1 = null;
    String[] s2 = null;

    Set<String> res = Stream.of(s1, s2)
                .filter(Objects::nonNull)  // <-- Filter out null values
                .flatMap(Stream::of)
                .collect(Collectors.toSet());
    Assert.assertNotNull(res);
    Assert.assertEquals(0,res.size());


    s1 = new String[]{"1","2"};
    Set<String> res2 = Stream.of(s1, s2)
                .filter(Objects::nonNull)  // <-- Filter out null values
                .flatMap(Stream::of)       // two arrays to one stream
                .collect(Collectors.toSet());
    Assert.assertNotNull(res2);
    Assert.assertEquals(2,res2.size());

    s2 = new String[]{"3","4"};
    Set<String> res3 = Stream.of(s1, s2)
                .filter(Objects::nonNull)  // <-- Filter out null values
                .flatMap(Stream::of)       // two arrays to one stream
                .collect(Collectors.toSet());
    Assert.assertNotNull(res3);
    Assert.assertEquals(4,res3.size());
    Assert.assertNotNull(res3.iterator().next());
}