Adjust checkstyle rules. Make checkstyle fail the build when violations are found. Correct all current checkstyle violations.

iterator/src/main/java/com/iluwatar/iterator/App.java

@@ -20,28 +20,28 @@ public class App {
   public static void main(String[] args) {
     TreasureChest chest = new TreasureChest();
 
-    ItemIterator ringIterator = chest.Iterator(ItemType.RING);
+    ItemIterator ringIterator = chest.iterator(ItemType.RING);
     while (ringIterator.hasNext()) {
       System.out.println(ringIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator potionIterator = chest.Iterator(ItemType.POTION);
+    ItemIterator potionIterator = chest.iterator(ItemType.POTION);
     while (potionIterator.hasNext()) {
       System.out.println(potionIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator weaponIterator = chest.Iterator(ItemType.WEAPON);
+    ItemIterator weaponIterator = chest.iterator(ItemType.WEAPON);
     while (weaponIterator.hasNext()) {
       System.out.println(weaponIterator.next());
     }
 
     System.out.println("----------");
 
-    ItemIterator it = chest.Iterator(ItemType.ANY);
+    ItemIterator it = chest.iterator(ItemType.ANY);
     while (it.hasNext()) {
       System.out.println(it.next());
     }

iterator/src/main/java/com/iluwatar/iterator/TreasureChest.java

@@ -12,6 +12,9 @@ public class TreasureChest {
 
   private List<Item> items;
 
+  /**
+   * Constructor
+   */
   public TreasureChest() {
     items = new ArrayList<>();
     items.add(new Item(ItemType.POTION, "Potion of courage"));
@@ -26,10 +29,13 @@ public class TreasureChest {
     items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
   }
 
-  ItemIterator Iterator(ItemType type) {
-    return new TreasureChestItemIterator(this, type);
+  ItemIterator iterator(ItemType itemType) {
+    return new TreasureChestItemIterator(this, itemType);
   }
 
+  /**
+   * Get all items
+   */
   public List<Item> getItems() {
     ArrayList<Item> list = new ArrayList<>();
     list.addAll(items);

iterator/src/main/java/com/iluwatar/iterator/TreasureChestItemIterator.java

@@ -13,6 +13,9 @@ public class TreasureChestItemIterator implements ItemIterator {
   private int idx;
   private ItemType type;
 
+  /**
+   * Constructor
+   */
   public TreasureChestItemIterator(TreasureChest chest, ItemType type) {
     this.chest = chest;
     this.type = type;

iterator/src/test/java/com/iluwatar/iterator/TreasureChestTest.java

@@ -60,7 +60,7 @@ public class TreasureChestTest {
   @Test
   public void testIterator() {
     final TreasureChest chest = new TreasureChest();
-    final ItemIterator iterator = chest.Iterator(expectedItem.getType());
+    final ItemIterator iterator = chest.iterator(expectedItem.getType());
     assertNotNull(iterator);
 
     while (iterator.hasNext()) {