[BAEL-3149] Java 'private' access modifier (#7622)

* Added private access modifier to tutorials

* added private access modifier example to core-lang-2 module

* [BAEL-3149] Java 'private' access modifier

* Update core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/Employee.java

Co-Authored-By: KevinGilmore <kpg102@gmail.com>

* Update core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/Employee.java

Co-Authored-By: KevinGilmore <kpg102@gmail.com>

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/Employee.java

@@ -0,0 +1,50 @@
+package com.baeldung.core.modifiers;
+
+public class Employee {
+
+    private String privateId;
+    public String name;
+    private boolean manager;
+
+    public Employee(String id, String name) {
+        changeId(id);
+        this.name = name;
+    }
+
+    private Employee(String id, String name, boolean managerAttribute) {
+        this.privateId = id;
+        this.name = name;
+        this.privateId = id + "_ID-MANAGER";
+    }
+
+    public void changeId(String customId) {
+        if (customId.endsWith("_ID")) {
+            this.privateId = customId;
+        } else {
+            this.privateId = customId + "_ID";
+        }
+    }
+
+    public String getId() {
+        return privateId;
+    }
+
+    public boolean isManager() {
+        return manager;
+    }
+
+    public void elevateToManager() {
+        if ("Carl".equals(this.name)) {
+            setManager(true);
+        }
+    }
+
+    private void setManager(boolean manager) {
+        this.manager = manager;
+    }
+
+    public static Employee buildManager(String id, String name) {
+        return new Employee(id, name, true);
+    }
+    
+}

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/ExampleClass.java

@@ -0,0 +1,10 @@
+package com.baeldung.core.modifiers;
+
+public class ExampleClass {
+
+    public static void main(String[] args) {
+        Employee employee = new Employee("Bob","ABC123");
+        employee.changeId("BCD234");
+        System.out.println(employee.getId());
+    }
+}

core-java-modules/core-java-lang-oop-2/src/main/java/com/baeldung/core/modifiers/PublicOuterClass.java

@@ -0,0 +1,16 @@
+package com.baeldung.core.modifiers;
+
+public class PublicOuterClass {
+
+    public PrivateInnerClass getInnerClassInstance() {
+        PrivateInnerClass myPrivateClassInstance = this.new PrivateInnerClass();
+        myPrivateClassInstance.id = "ID1";
+        myPrivateClassInstance.name = "Bob";
+        return myPrivateClassInstance;
+    }
+
+    private class PrivateInnerClass {
+        public String name;
+        public String id;
+    }
+}