BAEL-19 introduce basic concstruct

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

@@ -1,3 +1,6 @@
 package com.baeldung
 
-data class Item(val id: String, val name: String = "unknown_name")
+open class Item(val id: String, val name: String = "unknown_name")
+
+class ItemWithCategory(id: String, name: String, val categoryId: String) : Item(id, name)
+

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

@@ -5,6 +5,43 @@ import java.util.*
 class ItemService {
     fun findItemNameForId(id: String): Item? {
         val itemId = UUID.randomUUID().toString()
-        return Item(itemId, "name-$itemId");
+        return Item(itemId, "name-$itemId")
     }
+}
+
+class ItemManager(val categoryId: String, val dbConnection: String) {
+    var email = ""
+
+    constructor(categoryId: String, dbConnection: String, email: String) : this(categoryId, dbConnection) {
+        this.email = email
+    }
+
+    fun isFromSpecificCategory(catId: String): Boolean {
+        return categoryId == catId
+    }
+
+    fun makeAnalyisOfCategory(catId: String): Unit {
+        val result = if (catId == "100") "Yes" else "No"
+        println(result)
+
+    }
+}
+
+fun main(args: Array<String>) {
+    val numbers = arrayOf("first", "second", "third", "fourth")
+
+    for (n in numbers) {
+        println(n)
+    }
+
+    for (i in 0..9) {
+        println(i)
+    }
+
+    val firstName = "Tom"
+    val secondName = "Mary"
+    println("Names: $firstName, $secondName")
+
+    val itemManager = ItemManager("cat_id", "db://connection")
+    print("function result: ${itemManager.isFromSpecificCategory("1")}")
 }