diff --git a/Java/pom.xml b/Java/pom.xml
index 5d65fa0b..e9c8f5d8 100644
--- a/Java/pom.xml
+++ b/Java/pom.xml
@@ -13,15 +13,40 @@
         <java.version>1.8</java.version>
         <junit.jupiter.version>5.6.2</junit.jupiter.version>
         <maven.maven-surefire-plugin.version>3.0.0-M4</maven.maven-surefire-plugin.version>
+        <assertj-core.version>3.16.1</assertj-core.version>
+        <commons-lang3.version>3.10</commons-lang3.version>
+        <mockito.version>3.3.3</mockito.version>
     </properties>
 
     <dependencies>
+
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
             <version>${junit.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj-core.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
 
     <build>
diff --git a/Java/src/main/java/com/gildedrose/GRItem.java b/Java/src/main/java/com/gildedrose/GRItem.java
new file mode 100644
index 00000000..8132a3b5
--- /dev/null
+++ b/Java/src/main/java/com/gildedrose/GRItem.java
@@ -0,0 +1,97 @@
+package com.gildedrose;
+
+public class GRItem {
+
+    private static final String AGED_BRIE = "Aged Brie";
+    private static final String SULFURAS = "Sulfuras, Hand of Ragnaros";
+    private static final int MAX_QUALITY = 50;
+    private static final int MIN_QUALITY = 0;
+
+    private final Item item;
+
+    public GRItem(Item item) {
+        this.item = item;
+    }
+
+    public GRItem(String name, int sellIn, int quality) {
+        this.item = new Item(name, sellIn, quality);
+    }
+
+    public String getName() {
+        return item.name;
+    }
+
+    public int getSellIn() {
+        return item.sellIn;
+    }
+
+    public int getQuality() {
+        return item.quality;
+    }
+
+    public void updateQuality() {
+        if (!item.name.equals(AGED_BRIE)
+                && !item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+            if (item.quality > 0) {
+                if (!item.name.equals(SULFURAS)) {
+                    item.quality = item.quality - 1;
+                }
+            }
+        } else {
+            if (item.quality < MAX_QUALITY) {
+                item.quality = item.quality + 1;
+
+                if (item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                    if (item.sellIn < 11) {
+                        if (item.quality < MAX_QUALITY) {
+                            item.quality = item.quality + 1;
+                        }
+                    }
+
+                    if (item.sellIn < 6) {
+                        if (item.quality < MAX_QUALITY) {
+                            item.quality = item.quality + 1;
+                        }
+                    }
+                }
+            }
+        }
+
+        if (!item.name.equals(SULFURAS)) {
+            item.sellIn = item.sellIn - 1;
+        }
+
+        if (item.sellIn < 0) {
+            if (!item.name.equals(AGED_BRIE)) {
+                if (!item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
+                    if (item.quality > MIN_QUALITY) {
+                        if (!item.name.equals(SULFURAS)) {
+                            item.quality = item.quality - 1;
+                        }
+                    }
+                } else {
+                    item.quality = 0;
+                }
+            } else {
+                if (item.quality < MAX_QUALITY) {
+                    item.quality = item.quality + 1;
+                }
+            }
+        }
+    }
+
+    public static void validateItem(Item item) {
+        if (item.quality < GRItem.MIN_QUALITY) {
+            throw new ItemQualityIsNegativeException(item.name);
+        } else if (item.quality > GRItem.MAX_QUALITY && !item.name.equals(SULFURAS)) {
+            throw new ItemQualityExceedsMaxValueException(item.name);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "GRItem{" +
+                "item=" + item +
+                '}';
+    }
+}
diff --git a/Java/src/main/java/com/gildedrose/GildedRose.java b/Java/src/main/java/com/gildedrose/GildedRose.java
index e6feb751..3942c4de 100644
--- a/Java/src/main/java/com/gildedrose/GildedRose.java
+++ b/Java/src/main/java/com/gildedrose/GildedRose.java
@@ -1,62 +1,16 @@
 package com.gildedrose;
 
+import java.util.Arrays;
+
 class GildedRose {
     Item[] items;
 
     public GildedRose(Item[] items) {
+        Arrays.stream(items).forEach(GRItem::validateItem);
         this.items = items;
     }
 
     public void updateQuality() {
-        for (int i = 0; i < items.length; i++) {
-            if (!items[i].name.equals("Aged Brie")
-                    && !items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                if (items[i].quality > 0) {
-                    if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                        items[i].quality = items[i].quality - 1;
-                    }
-                }
-            } else {
-                if (items[i].quality < 50) {
-                    items[i].quality = items[i].quality + 1;
-
-                    if (items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                        if (items[i].sellIn < 11) {
-                            if (items[i].quality < 50) {
-                                items[i].quality = items[i].quality + 1;
-                            }
-                        }
-
-                        if (items[i].sellIn < 6) {
-                            if (items[i].quality < 50) {
-                                items[i].quality = items[i].quality + 1;
-                            }
-                        }
-                    }
-                }
-            }
-
-            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                items[i].sellIn = items[i].sellIn - 1;
-            }
-
-            if (items[i].sellIn < 0) {
-                if (!items[i].name.equals("Aged Brie")) {
-                    if (!items[i].name.equals("Backstage passes to a TAFKAL80ETC concert")) {
-                        if (items[i].quality > 0) {
-                            if (!items[i].name.equals("Sulfuras, Hand of Ragnaros")) {
-                                items[i].quality = items[i].quality - 1;
-                            }
-                        }
-                    } else {
-                        items[i].quality = items[i].quality - items[i].quality;
-                    }
-                } else {
-                    if (items[i].quality < 50) {
-                        items[i].quality = items[i].quality + 1;
-                    }
-                }
-            }
-        }
+        Arrays.stream(items).map(GRItem::new).forEach(GRItem::updateQuality);
     }
 }
\ No newline at end of file
diff --git a/Java/src/main/java/com/gildedrose/Item.java b/Java/src/main/java/com/gildedrose/Item.java
index 465729ec..19634c6d 100644
--- a/Java/src/main/java/com/gildedrose/Item.java
+++ b/Java/src/main/java/com/gildedrose/Item.java
@@ -14,8 +14,8 @@ public class Item {
         this.quality = quality;
     }
 
-   @Override
-   public String toString() {
+    @Override
+    public String toString() {
         return this.name + ", " + this.sellIn + ", " + this.quality;
     }
 }
diff --git a/Java/src/main/java/com/gildedrose/ItemQualityExceedsMaxValueException.java b/Java/src/main/java/com/gildedrose/ItemQualityExceedsMaxValueException.java
new file mode 100644
index 00000000..d80fbd42
--- /dev/null
+++ b/Java/src/main/java/com/gildedrose/ItemQualityExceedsMaxValueException.java
@@ -0,0 +1,8 @@
+package com.gildedrose;
+
+public class ItemQualityExceedsMaxValueException extends RuntimeException {
+
+    public ItemQualityExceedsMaxValueException(String name) {
+        super("Item '" + name + "' exceeds max value for quality ");
+    }
+}
diff --git a/Java/src/main/java/com/gildedrose/ItemQualityIsNegativeException.java b/Java/src/main/java/com/gildedrose/ItemQualityIsNegativeException.java
new file mode 100644
index 00000000..1d9bf8ff
--- /dev/null
+++ b/Java/src/main/java/com/gildedrose/ItemQualityIsNegativeException.java
@@ -0,0 +1,8 @@
+package com.gildedrose;
+
+public class ItemQualityIsNegativeException extends RuntimeException {
+
+    public ItemQualityIsNegativeException(String name) {
+        super("Item '" + name + "' has a negative quality value");
+    }
+}
diff --git a/Java/src/test/java/com/gildedrose/GRItemConstructorTest.java b/Java/src/test/java/com/gildedrose/GRItemConstructorTest.java
new file mode 100644
index 00000000..c7a20d67
--- /dev/null
+++ b/Java/src/test/java/com/gildedrose/GRItemConstructorTest.java
@@ -0,0 +1,22 @@
+package com.gildedrose;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class GRItemConstructorTest {
+
+    private static final String NAME = "+5 Dexterity Vest";
+    private static final int SELL_IN = 10;
+    private static final int QUALITY = 20;
+
+    @Test
+    public void constructsCorrectly() {
+        Item item = new Item(NAME, SELL_IN, QUALITY);
+        GRItem grItem = new GRItem(item);
+
+        assertThat(grItem.getName()).isEqualTo(NAME);
+        assertThat(grItem.getSellIn()).isEqualTo(SELL_IN);
+        assertThat(grItem.getQuality()).isEqualTo(QUALITY);
+    }
+}
diff --git a/Java/src/test/java/com/gildedrose/GRItemUpdateQualityTest.java b/Java/src/test/java/com/gildedrose/GRItemUpdateQualityTest.java
new file mode 100644
index 00000000..67868dbe
--- /dev/null
+++ b/Java/src/test/java/com/gildedrose/GRItemUpdateQualityTest.java
@@ -0,0 +1,114 @@
+package com.gildedrose;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+import static org.apache.commons.lang3.RandomStringUtils.random;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class GRItemUpdateQualityTest {
+    private static final String AGED_BRIE = "Aged Brie";
+    private static final String SULFURAS = "Sulfuras, Hand of Ragnaros";
+    private static final String BACKSTAGE_PASSES = "Backstage passes to a TAFKAL80ETC concert";
+
+    @Test
+    public void lowersTheSellInValue() {
+        GRItem item = new GRItem(random(5), 10, 20);
+        item.updateQuality();
+
+        assertThat(item.getSellIn()).isEqualTo(9);
+    }
+
+    @Test
+    public void qualityDegrades() {
+        GRItem item = new GRItem(random(5), 10, 20);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(19);
+    }
+
+    @Test
+    public void qualityDegradesTwiceAsFastWhenSellByDatePassed() {
+        GRItem item = new GRItem(random(5), 0, 20);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(18);
+    }
+
+    @Test
+    public void qualityIsNeverNegative() {
+        GRItem item = new GRItem(random(5), 10, 0);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(0);
+    }
+
+    @Test
+    public void qualityOfAgedBrieIncreases() {
+        GRItem item = new GRItem(AGED_BRIE, 10, 10);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(11);
+    }
+
+    @Test
+    public void qualityOfAgedBrieIncreasesEvenWhenSellInIsNegative() {
+        GRItem item = new GRItem(AGED_BRIE, -1, 10);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(12);
+    }
+
+    @Test
+    public void qualityIncreasesNeverHigherThan50() {
+        GRItem item = new GRItem(AGED_BRIE, 10, 50);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(50);
+    }
+
+    @ParameterizedTest(name = "with quality {0}")
+    @ValueSource(ints = {-1, 0, 1, 20, 50})
+    public void qualityOfSulfurasNeverAlters(int quality) {
+        GRItem item = new GRItem(SULFURAS, 10, quality);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(quality);
+    }
+
+    @Test
+    public void sellInOfSulfurasNeverAlters() {
+        GRItem item = new GRItem(SULFURAS, 10, 20);
+        item.updateQuality();
+
+        assertThat(item.getSellIn()).isEqualTo(10);
+    }
+
+    @ParameterizedTest(name = "with sellIn {0}")
+    @ValueSource(ints = {10, 9, 8, 7, 6})
+    public void qualityOfBackstagePassesIncreaseBy2WhenSellIn10DaysOrLess(int sellIn) {
+        GRItem item = new GRItem(BACKSTAGE_PASSES, sellIn, 10);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(12);
+    }
+
+    @ParameterizedTest(name = "with sellIn {0}")
+    @ValueSource(ints = {5, 4, 3, 2, 1})
+    public void qualityOfBackstagePassesIncreaseBy3WhenSellIn5DaysOrLess(int sellIn) {
+        GRItem item = new GRItem(BACKSTAGE_PASSES, sellIn, 10);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(13);
+    }
+
+    @ParameterizedTest(name = "with sellIn {0}")
+    @ValueSource(ints = {0, -1})
+    public void qualityOfBackstagePassesIsZeroAfterConcert(int sellIn) {
+        GRItem item = new GRItem(BACKSTAGE_PASSES, sellIn, 10);
+        item.updateQuality();
+
+        assertThat(item.getQuality()).isEqualTo(0);
+    }
+}
diff --git a/Java/src/test/java/com/gildedrose/GRItemValidateItemTest.java b/Java/src/test/java/com/gildedrose/GRItemValidateItemTest.java
new file mode 100644
index 00000000..957aabba
--- /dev/null
+++ b/Java/src/test/java/com/gildedrose/GRItemValidateItemTest.java
@@ -0,0 +1,33 @@
+package com.gildedrose;
+
+import org.junit.jupiter.api.Test;
+
+import static org.apache.commons.lang3.RandomStringUtils.random;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+class GRItemValidateItemTest {
+
+    private static final String SULFURAS = "Sulfuras, Hand of Ragnaros";
+
+    @Test
+    public void throwsExceptionWhenItemValueIsNegative() {
+        Item item = new Item(random(5), 10, -1);
+
+        assertThatThrownBy(() -> GRItem.validateItem(item)).isInstanceOf(ItemQualityIsNegativeException.class);
+    }
+
+    @Test
+    public void throwsExceptionWhenItemValueExceedsMaxValue() {
+        Item item = new Item(random(5), 10, 51);
+
+        assertThatThrownBy(() -> GRItem.validateItem(item)).isInstanceOf(ItemQualityExceedsMaxValueException.class);
+    }
+
+
+    @Test
+    public void doesNotThrowExceptionWhenItemValueExceedsMaxValueAndItemIsSulfuras() {
+        Item item = new Item(SULFURAS, 10, 51);
+
+        GRItem.validateItem(item);
+    }
+}
\ No newline at end of file
diff --git a/Java/src/test/java/com/gildedrose/GildedRoseTest.java b/Java/src/test/java/com/gildedrose/GildedRoseTest.java
deleted file mode 100644
index 8ae29eec..00000000
--- a/Java/src/test/java/com/gildedrose/GildedRoseTest.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package com.gildedrose;
-
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-class GildedRoseTest {
-
-    @Test
-    void foo() {
-        Item[] items = new Item[] { new Item("foo", 0, 0) };
-        GildedRose app = new GildedRose(items);
-        app.updateQuality();
-        assertEquals("fixme", app.items[0].name);
-    }
-
-}
diff --git a/Java/src/test/java/com/gildedrose/GildedRoseUpdateQualityTest.java b/Java/src/test/java/com/gildedrose/GildedRoseUpdateQualityTest.java
new file mode 100644
index 00000000..cd7ccd2d
--- /dev/null
+++ b/Java/src/test/java/com/gildedrose/GildedRoseUpdateQualityTest.java
@@ -0,0 +1,34 @@
+package com.gildedrose;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mock;
+
+import static org.apache.commons.lang3.RandomStringUtils.random;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class GildedRoseUpdateQualityTest {
+
+    private GildedRose gildedRose;
+
+    @BeforeEach
+    void setUp() {
+        Item[] items = new Item[]{
+                new Item("+5 Dexterity Vest", 10, 20),
+                new Item("Aged Brie", 2, 0),
+                new Item("Elixir of the Mongoose", 5, 7),
+                new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20),
+        };
+
+        gildedRose = new GildedRose(items);
+    }
+
+    @Test
+    public void updatesTheQualityOfAllItems() {
+        assertThat(gildedRose.items).extracting(i -> i.quality).containsExactly(20, 0, 7, 20);
+        gildedRose.updateQuality();
+        assertThat(gildedRose.items).extracting(i -> i.quality).containsExactly(19, 1, 6, 21);
+    }
+
+}
diff --git a/Java/src/test/java/com/gildedrose/GuildedRoseConstructorTest.java b/Java/src/test/java/com/gildedrose/GuildedRoseConstructorTest.java
new file mode 100644
index 00000000..fdb42eca
--- /dev/null
+++ b/Java/src/test/java/com/gildedrose/GuildedRoseConstructorTest.java
@@ -0,0 +1,17 @@
+package com.gildedrose;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+public class GuildedRoseConstructorTest {
+
+    @Test
+    public void validatesInitialItemQualities() {
+        Item[] items = new Item[]{
+                new Item("+5 Dexterity Vest", 10, -1)
+        };
+
+        assertThatThrownBy(() -> new GildedRose(items)).isInstanceOf(ItemQualityIsNegativeException.class);
+    }
+}