Nested Classes in Java

core-java/src/main/java/com/baeldung/nestedclass/Enclosing.java

@@ -0,0 +1,11 @@
+package com.baeldung.nestedclass;
+
+public class Enclosing {
+
+    public static class Nested {
+
+        public void test() {
+            System.out.println("Calling test...");
+        }
+    }
+}

core-java/src/main/java/com/baeldung/nestedclass/NewEnclosing.java

@@ -0,0 +1,15 @@
+package com.baeldung.nestedclass;
+
+public class NewEnclosing {
+
+    void run() {
+        class Local {
+
+            void run() {
+                System.out.println("Welcome to Baeldung!");
+            }
+        }
+        Local local = new Local();
+        local.run();
+    }
+}

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

@@ -0,0 +1,11 @@
+package com.baeldung.nestedclass;
+
+public class Outer {
+
+    public class Inner {
+
+        public void test() {
+            System.out.println("Calling test...");
+        }
+    }
+}

core-java/src/main/java/com/baeldung/nestedclass/SimpleAbstractClass.java

@@ -0,0 +1,5 @@
+package com.baeldung.nestedclass;
+
+abstract class SimpleAbstractClass {
+    abstract void run();
+}

core-java/src/test/java/com/baeldung/nestedclass/AnonymousInnerTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.nestedclass;
+
+import org.junit.Test;
+
+public class AnonymousInnerTest {
+
+    @Test
+    public void whenRunAnonymousClass_thenCorrect() {
+        SimpleAbstractClass simpleAbstractClass = new SimpleAbstractClass() {
+            void run() {
+                System.out.println("Running Anonymous Class...");
+            }
+        };
+        simpleAbstractClass.run();
+    }
+}

core-java/src/test/java/com/baeldung/nestedclass/InnerClassTest.java

@@ -0,0 +1,13 @@
+package com.baeldung.nestedclass;
+
+import org.junit.Test;
+
+public class InnerClassTest {
+
+    @Test
+    public void givenInnerClassWhenInstantiating_thenCorrect() {
+        Outer outer = new Outer();
+        Outer.Inner inner = outer.new Inner();
+        inner.test();
+    }
+}

core-java/src/test/java/com/baeldung/nestedclass/LocalClassTest.java

@@ -0,0 +1,12 @@
+package com.baeldung.nestedclass;
+
+import org.junit.Test;
+
+public class LocalClassTest {
+
+    @Test
+    public void whenTestingLocalClass_thenCorrect() {
+        NewEnclosing newEnclosing = new NewEnclosing();
+        newEnclosing.run();
+    }
+}

core-java/src/test/java/com/baeldung/nestedclass/NestedClassTest.java

@@ -0,0 +1,12 @@
+package com.baeldung.nestedclass;
+
+import org.junit.Test;
+
+public class NestedClassTest {
+
+    @Test
+    public void whenInstantiatingStaticNestedClass_thenCorrect() {
+        Enclosing.Nested nested = new Enclosing.Nested();
+        nested.test();
+    }
+}

core-java/src/test/java/com/baeldung/nestedclass/NewOuterTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.nestedclass;
+
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+public class NewOuterTest {
+
+    int a = 1;
+    static int b = 2;
+
+    public class InnerClass {
+        int a = 3;
+        static final int b = 4;
+
+        @Test
+        public void whenShadowing_thenCorrect() {
+            assertEquals(3, a);
+            assertEquals(4, b);
+            assertEquals(1, NewOuterTest.this.a);
+            assertEquals(2, NewOuterTest.b);
+            assertEquals(2, NewOuterTest.this.b);
+        }
+    }
+
+    @Test
+    public void shadowingTest() {
+        NewOuterTest outer = new NewOuterTest();
+        NewOuterTest.InnerClass inner = outer.new InnerClass();
+        inner.whenShadowing_thenCorrect();
+
+    }
+}