Merge pull request #5977 from rockoder/java11-nests

[BAEL-2359] Java 11 Nests

core-java-11/src/main/java/com/baeldung/Outer.java

@@ -0,0 +1,24 @@
+package com.baeldung;
+
+import java.lang.reflect.Method;
+
+public class Outer {
+
+    public void outerPublic() {
+    }
+
+    private void outerPrivate() {
+    }
+
+    class Inner {
+
+        public void innerPublic() {
+            outerPrivate();
+        }
+
+        public void innerPublicReflection(Outer ob) throws Exception {
+            Method method = ob.getClass().getDeclaredMethod("outerPrivate");
+            method.invoke(ob);
+        }
+    }
+}

core-java-11/src/test/java/com/baeldung/OuterUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung;
+
+import static org.junit.Assert.assertTrue;
+import static org.hamcrest.CoreMatchers.is;
+
+import java.util.Arrays;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.junit.Test;
+
+public class OuterUnitTest {
+
+    private static final String NEST_HOST_NAME = "com.baeldung.Outer";
+
+    @Test
+    public void whenGetNestHostFromOuter_thenGetNestHost() {
+        is(Outer.class.getNestHost().getName()).equals(NEST_HOST_NAME);
+    }
+
+    @Test
+    public void whenGetNestHostFromInner_thenGetNestHost() {
+        is(Outer.Inner.class.getNestHost().getName()).equals(NEST_HOST_NAME);
+    }
+
+    @Test
+    public void whenCheckNestmatesForNestedClasses_thenGetTrue() {
+        is(Outer.Inner.class.isNestmateOf(Outer.class)).equals(true);
+    }
+
+    @Test
+    public void whenCheckNestmatesForUnrelatedClasses_thenGetFalse() {
+        is(Outer.Inner.class.isNestmateOf(Outer.class)).equals(false);
+    }
+
+    @Test
+    public void whenGetNestMembersForNestedClasses_thenGetAllNestedClasses() {
+        Set<String> nestMembers = Arrays.stream(Outer.Inner.class.getNestMembers())
+          .map(Class::getName)
+          .collect(Collectors.toSet());
+
+        is(nestMembers.size()).equals(2);
+
+        assertTrue(nestMembers.contains("com.baeldung.Outer"));
+        assertTrue(nestMembers.contains("com.baeldung.Outer$Inner"));
+    }
+}