Fix/kotlin equality (#1861)

* Add project for hibernate immutable article
Add Event entity
Add hibernate configuration file
Add hibernateutil for configuration
Add test to match snippets from article

* Update master

* Add simplet test to check Kotlin rerence vs strutural equality

* Update README

* Kotlin equality - fix
Add suite of tests for complex object and arrays
Add User class

kotlin/src/main/kotlin/com/baeldung/kotlin/User.kt

@@ -0,0 +1,3 @@
+package com.baeldung.kotlin
+
+data class User(val name: String, val age: Int, val hobbies: List<String>)

kotlin/src/test/kotlin/com/baeldung/kotlin/EqualityTest.kt

@@ -23,4 +23,36 @@ class EqualityTest {
 
         assertTrue(a == b)
     }
+
+    @Test
+    fun givenUser_whenCheckReference_thenEqualReference() {
+        val user = User("John", 30, listOf("Hiking, Chess"))
+        val user2 = User("Sarah", 28, listOf("Shopping, Gymnastics"))
+
+        assertFalse(user === user2)
+    }
+
+    @Test
+    fun givenUser_whenCheckValue_thenStructurallyEqual() {
+        val user = User("John", 30, listOf("Hiking, Chess"))
+        val user2 = User("John", 30, listOf("Hiking, Chess"))
+
+        assertTrue(user == user2)
+    }
+
+    @Test
+    fun givenArray_whenCheckReference_thenEqualReference() {
+        val hobbies = arrayOf("Riding motorcycle, Video games")
+        val hobbies2 = arrayOf("Riding motorcycle, Video games")
+
+        assertFalse(hobbies === hobbies2)
+    }
+
+    @Test
+    fun givenArray_whenCheckContent_thenStructurallyEqual() {
+        val hobbies = arrayOf("Hiking, Chess")
+        val hobbies2 = arrayOf("Hiking, Chess")
+
+        assertTrue(hobbies contentEquals hobbies2)
+    }
 }