添加 Optional 类的测试文件和文章说明连接： https://www.ossez.com/t/java-8-optional/13964

core-java-modules/core-java-11-2/README.md

@@ -3,7 +3,7 @@
 本模块中包含有关 Java 11 核心新增功能的的一些文章
 
 ### 相关文章
-- [Guide to Java 8 Optional](https://www.baeldung.com/java-optional)
+- [Java 8 开始新增的 Optional 类](https://www.ossez.com/t/java-8-optional/13964)
 - [Guide to Java Reflection](http://www.baeldung.com/java-reflection)
 - [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
 - [New Features in Java 11](https://www.baeldung.com/java-11-new-features)

core-java-modules/core-java-11-2/src/test/java/com/ossez/optional/OptionalUnitTest.java

@@ -76,16 +76,16 @@ public class OptionalUnitTest {
     // Condition Action With ifPresent()
     @Test
     public void givenOptional_whenIfPresentWorks_thenCorrect() {
-        Optional<String> opt = Optional.of("baeldung");
+        Optional<String> opt = Optional.of("HoneyMoose");
         opt.ifPresent(name -> LOG.debug("{}", name.length()));
     }
 
     // returning Value With get()
     @Test
     public void givenOptional_whenGetsValue_thenCorrect() {
-        Optional<String> opt = Optional.of("baeldung");
+        Optional<String> opt = Optional.of("HoneyMoose");
         String name = opt.get();
-        assertEquals("baeldung", name);
+        assertEquals("HoneyMoose", name);
     }
 
     @Test(expected = NoSuchElementException.class)
@@ -96,13 +96,23 @@ public class OptionalUnitTest {
 
     @Test
     public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected() {
-        Optional<String> opt = Optional.of("Baeldung");
+        Optional<String> opt = Optional.of("HoneyMoose");
         assertTrue(opt.isPresent());
 
         opt = Optional.ofNullable(null);
         assertFalse(opt.isPresent());
     }
 
+    // This code only can be run in JDK 11
+    @Test
+    public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected_JDK11() {
+        Optional<String> opt = Optional.of("Baeldung");
+        assertFalse(opt.isEmpty());
+
+        opt = Optional.ofNullable(null);
+        assertTrue(opt.isEmpty());
+    }
+
     // Conditional Return With filter()
     @Test
     public void whenOptionalFilterWorks_thenCorrect() {
@@ -157,11 +167,11 @@ public class OptionalUnitTest {
 
     @Test
     public void givenOptional_whenMapWorks_thenCorrect2() {
-        String name = "baeldung";
+        String name = "HoneyMoose";
         Optional<String> nameOptional = Optional.of(name);
 
         int len = nameOptional.map(String::length).orElse(0);
-        assertEquals(8, len);
+        assertEquals(10, len);
     }
 
     @Test
@@ -214,7 +224,6 @@ public class OptionalUnitTest {
         String nullName = null;
         String name = Optional.ofNullable(nullName).orElseGet(() -> "john");
         assertEquals("john", name);
-
     }
 
     @Test
@@ -259,14 +268,5 @@ public class OptionalUnitTest {
         return "Default Value";
     }
 
-//    Uncomment code when code base is compatible with Java 11
-//    @Test
-//    public void givenAnEmptyOptional_thenIsEmptyBehavesAsExpected() {
-//        Optional<String> opt = Optional.of("Baeldung");
-//        assertFalse(opt.isEmpty());
-//     
-//        opt = Optional.ofNullable(null);
-//        assertTrue(opt.isEmpty());
-//    }
 
 }