Merge remote-tracking branch 'upstream/master'

# Conflicts:
#	core-java-9/pom.xml
#	core-java-9/src/test/java/com/baeldung/java9/MultiResultionImageTest.java

core-java-9/src/test/java/com/baeldung/java9/Java9OptionalsStreamTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.java8;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class Java9OptionalsStreamTest {
+
+    private static List<Optional<String>> listOfOptionals = Arrays.asList(Optional.empty(), Optional.of("foo"), Optional.empty(), Optional.of("bar"));
+
+    @Test
+    public void filterOutPresentOptionalsWithFilter() {
+        assertEquals(4, listOfOptionals.size());
+
+        List<String> filteredList = listOfOptionals.stream()
+          .filter(Optional::isPresent)
+          .map(Optional::get)
+          .collect(Collectors.toList());
+
+        assertEquals(2, filteredList.size());
+        assertEquals("foo", filteredList.get(0));
+        assertEquals("bar", filteredList.get(1));
+    }
+
+    @Test
+    public void filterOutPresentOptionalsWithFlatMap() {
+        assertEquals(4, listOfOptionals.size());
+
+        List<String> filteredList = listOfOptionals.stream()
+          .flatMap(o -> o.isPresent() ? Stream.of(o.get()) : Stream.empty())
+          .collect(Collectors.toList());
+        assertEquals(2, filteredList.size());
+
+        assertEquals("foo", filteredList.get(0));
+        assertEquals("bar", filteredList.get(1));
+    }
+
+    @Test
+    public void filterOutPresentOptionalsWithJava9() {
+        assertEquals(4, listOfOptionals.size());
+
+        List<String> filteredList = listOfOptionals.stream()
+          .flatMap(Optional::stream)
+          .collect(Collectors.toList());
+
+        assertEquals(2, filteredList.size());
+        assertEquals("foo", filteredList.get(0));
+        assertEquals("bar", filteredList.get(1));
+    }
+
+}

core-java-9/src/test/java/com/baeldung/java9/MultiResultionImageTest.java

@@ -1,5 +1,5 @@
 package com.baeldung.java9;
-
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;