[BAEL-4208] Java compiled classes contain dollar signs (#10533)

Java class file naming conventions

Co-authored-by: MeenaGawande <MeenaGawande@users.noreply.github.com>

core-java-modules/core-java-lang-oop-types/src/main/java/com/baeldung/classfile/Outer.java

@@ -0,0 +1,131 @@
+package com.baeldung.classfile;
+
+import org.apache.commons.lang3.StringUtils;
+import com.baeldung.classfile.HelloWorld.HelloSomeone;
+
+public class Outer {
+
+    // Static Nested class
+    static class StaticNested {
+        public String message() {
+            return "This is a static Nested Class";
+        }
+    }
+
+    // Non-static Nested class
+    class Nested {
+        public String message() {
+            return "This is a non-static Nested Class";
+        }
+    }
+
+    // Local class
+    public String message() {
+        class Local {
+            private String message() {
+                return "This is a Local Class within a method";
+            }
+        }
+        Local local = new Local();
+        return local.message();
+    }
+
+    // Local class within if clause
+    public String message(String name) {
+        if (StringUtils.isEmpty(name)) {
+            class Local {
+                private String message() {
+                    return "This is a Local Class within if clause";
+                }
+            }
+            Local local = new Local();
+            return local.message();
+        } else
+            return "Welcome to " + name;
+    }
+
+    // Anonymous Inner class extending a class
+    public String greet() {
+        Outer anonymous = new Outer() {
+            public String greet() {
+                return "Running Anonymous Class...";
+            }
+        };
+        return anonymous.greet();
+    }
+
+    // Anonymous inner class implementing an interface
+    public String greet(String name) {
+
+        HelloWorld helloWorld = new HelloWorld() {
+            public String greet(String name) {
+                return "Welcome to " + name;
+            }
+
+        };
+        return helloWorld.greet(name);
+    }
+
+    // Anonymous inner class implementing nested interface
+    public String greetSomeone(String name) {
+
+        HelloSomeone helloSomeOne = new HelloSomeone() {
+            public String greet(String name) {
+                return "Hello " + name;
+            }
+
+        };
+        return helloSomeOne.greet(name);
+    }
+
+    // Nested interface within a class
+    interface HelloOuter {
+        public String hello(String name);
+    }
+
+    // Enum within a class
+    enum Color {
+        RED, GREEN, BLUE;
+    }
+}
+
+interface HelloWorld {
+
+    public String greet(String name);
+
+    // Nested class within an interface
+    class InnerClass {
+        public String greet(String name) {
+            return "Inner class within an interface";
+        }
+    }
+
+    // Nested interface within an interfaces
+    interface HelloSomeone {
+        public String greet(String name);
+    }
+
+    // Enum within an interface
+    enum Directon {
+        NORTH, SOUTH, EAST, WEST;
+    }
+}
+
+enum Level {
+    LOW, MEDIUM, HIGH;
+
+}
+
+enum Foods {
+
+    DRINKS, EATS;
+
+    // Enum within Enum
+    enum DRINKS {
+        APPLE_JUICE, COLA;
+    }
+
+    enum EATS {
+        POTATO, RICE;
+    }
+}

core-java-modules/core-java-lang-oop-types/src/test/java/com/baeldung/classfile/OuterUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.classfile;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
+import com.baeldung.classfile.Outer.Nested;
+
+public class OuterUnitTest {
+
+    @Test
+    public void when_static_nestedClass_then_verifyOutput() {
+        Outer.StaticNested nestedClass = new Outer.StaticNested();
+        assertEquals("This is a static Nested Class", nestedClass.message());
+    }
+
+    @Test
+    public void when_nestedClass_then_verifyOutput() {
+        Outer outer = new Outer();
+        Nested nestedClass = outer.new Nested();
+        assertEquals("This is a non-static Nested Class", nestedClass.message());
+    }
+
+    @Test
+    public void when_localClass_then_verifyOutput() {
+        Outer outer = new Outer();
+        assertEquals("This is a Local Class within a method", outer.message());
+    }
+
+    @Test
+    public void when_localClassInIfClause_then_verifyOutput() {
+        Outer outer = new Outer();
+        assertEquals("Welcome to Baeldung", outer.message("Baeldung"));
+        assertEquals("This is a Local Class within if clause", outer.message(""));
+    }
+
+    @Test
+    public void when_anonymousClass_then_verifyOutput() {
+        Outer outer = new Outer();
+        assertEquals("Running Anonymous Class...", outer.greet());
+    }
+
+    @Test
+    public void when_anonymousClassHelloWorld_then_verifyOutput() {
+        Outer outer = new Outer();
+        assertEquals("Welcome to Baeldung", outer.greet("Baeldung"));
+    }
+}