Create class for age brie items

Java/src/main/java/com/gildedrose/items/AgedBrieItem.java

@@ -0,0 +1,20 @@
+package com.gildedrose.items;
+
+import com.gildedrose.Quality;
+import com.gildedrose.SellIn;
+import lombok.EqualsAndHashCode;
+
+@EqualsAndHashCode(callSuper = true)
+public class AgedBrieItem extends GildedRoseItem {
+
+  public AgedBrieItem(SellIn sellIn, Quality quality, boolean conjured) {
+    super("Aged Brie", sellIn, quality, conjured);
+  }
+
+  @Override
+  protected Quality nextQuality(Quality previous) {
+    Quality nextQuality = previous.copy();
+    nextQuality.increment();
+    return nextQuality;
+  }
+}

Java/src/test/java/com/gildedrose/items/AgedBrieItemTest.java

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+package com.gildedrose.items;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.gildedrose.Quality;
+import com.gildedrose.SellIn;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+class AgedBrieItemTest {
+  private final AgedBrieItem item =
+      new AgedBrieItem(SellIn.create(2), Quality.create(0), Boolean.FALSE);
+
+  @Nested
+  class nextQuality {
+    @Test
+    void should_increment_quality_in_one() {
+      Quality nextQuality = item.nextQuality(Quality.create(0));
+
+      assertThat(nextQuality).isEqualTo(Quality.create(1));
+    }
+  }
+}