Add javadocs

Java/src/main/java/com/gildedrose/AgedBrie.java

@@ -1,6 +1,9 @@
 package com.gildedrose;
 
-public class AgedBrie extends RegularItem {
+/**
+ * Class for Aged Brie item inherited from NormalItem
+ */
+public class AgedBrie extends NormalItem {
 
     public AgedBrie(Item item) {
         this.item=item;

Java/src/main/java/com/gildedrose/BackStageItem.java

@@ -1,6 +1,12 @@
 package com.gildedrose;
 
-public class BackStageItem extends RegularItem{
+/**
+ * Class Back Stage item inherited form NormalItem
+ *
+ * Business rules are inherited from NormalItem with more conditions:
+ *  Quality increases by 2 when there are 10 days or less and by 3 when there are 5 days or less
+ */
+public class BackStageItem extends NormalItem {
     public BackStageItem(Item item) {
         this.item=item;
     }

Java/src/main/java/com/gildedrose/ConjuredItem.java

@@ -1,6 +1,9 @@
 package com.gildedrose;
 
-public class ConjuredItem extends RegularItem {
+/**
+ * Class for the item ConjuredItem inherited from NormalItem
+ */
+public class ConjuredItem extends NormalItem {
     public ConjuredItem(Item item) {
         this.item=item;
     }

Java/src/main/java/com/gildedrose/GildedRoseItem.java

@@ -1,5 +1,8 @@
 package com.gildedrose;
 
+/**
+ * Class which update quality for all items
+ */
 class GildedRoseItem {
     Item[] items;
     public static final String SULFURA = "Sulfuras, Hand of Ragnaros";
@@ -27,8 +30,8 @@ class GildedRoseItem {
             ConjuredItem conjuredItem = new ConjuredItem(item);
             conjuredItem.updateQuality();
         } else {
-           RegularItem regularItem = new RegularItem(item);
-           regularItem.updateQuality();
+           NormalItem normalItem = new NormalItem(item);
+           normalItem.updateQuality();
         }
     }
 

Java/src/main/java/com/gildedrose/NormalItem.java

@@ -1,13 +1,20 @@
 package com.gildedrose;
 
-public class RegularItem {
+/**
+ * Class for a regular item with business rule for normal item:
+ *  If the item expired => reduce the quality by 2 else reduce by 1
+ *  Quality for an item is never negative
+ *  Quality for an item is not greater than the constant MAX_QUAILITY_FOR_AN_ITEM
+ */
+public class NormalItem {
+    public static final int MAX_QUAILITY_FOR_AN_ITEM = 50;
     public Item item;
 
-    public RegularItem() {
+    public NormalItem() {
 
     }
 
-    public RegularItem(Item item) {
+    public NormalItem(Item item) {
         this.item = item;
     }
 
@@ -31,7 +38,7 @@ public class RegularItem {
 
     protected void increaseQualityBy(int factor) {
         item.quality += factor;
-        qualityOfAnItemIsNotMoreThan(50);
+        qualityOfAnItemIsNotMoreThan(MAX_QUAILITY_FOR_AN_ITEM);
     }
 
     protected void decreaseQualityBy(int factor) {

Java/src/test/java/com/gildedrose/GildedRoseItemTest.java

@@ -5,6 +5,9 @@ import java.util.HashMap;
 
 import org.junit.Test;
 
+/**
+ * Test the result of item.sellIn and item.quality after n days
+ */
 public class GildedRoseItemTest {
     private Item[] itemsSample = new Item[]{new Item("+5 Dexterity Vest", 10, 20), //
             new Item("Aged Brie", 2, 0), //