Use CraftItemStack where possible. The meta implementations are fuller. Especially noticeable with Shield banner pattern serialization and deserialization.

src/com/massivecraft/massivecore/item/WriterAbstractItemStack.java

@@ -1,8 +1,9 @@
 package com.massivecraft.massivecore.item;
 
-import org.bukkit.Material;
 import org.bukkit.inventory.ItemStack;
 
+import com.massivecraft.massivecore.nms.NmsItemStack;
+
 
 public abstract class WriterAbstractItemStack<FA, FB> extends WriterAbstract<DataItemStack, ItemStack, DataItemStack, ItemStack, FA, FB>
 {
@@ -19,7 +20,7 @@ public abstract class WriterAbstractItemStack<FA, FB> extends WriterAbstract<Dat
 	@Override
 	public ItemStack createB()
 	{
-		return new ItemStack(Material.AIR);
+		return NmsItemStack.get().createItemStack();
 	}
 	
 }

src/com/massivecraft/massivecore/item/WriterAbstractMeta.java

@@ -3,6 +3,8 @@ package com.massivecraft.massivecore.item;
 import org.bukkit.Material;
 import org.bukkit.inventory.ItemStack;
 
+import com.massivecraft.massivecore.nms.NmsItemStack;
+
 public abstract class WriterAbstractMeta<OB, CB, FA, FB> extends WriterAbstract<DataItemStack, OB, DataItemStack, CB, FA, FB>
 {
 	// -------------------------------------------- //
@@ -33,7 +35,9 @@ public abstract class WriterAbstractMeta<OB, CB, FA, FB> extends WriterAbstract<
 	@Override
 	public CB createB()
 	{
-		return (CB) new ItemStack(this.getMaterial()).getItemMeta();
+		ItemStack itemStack = NmsItemStack.get().createItemStack();
+		itemStack.setType(this.getMaterial());
+		return (CB) itemStack.getItemMeta();
 	}
 	
 }

src/com/massivecraft/massivecore/nms/NmsItemStack.java

@@ -0,0 +1,75 @@
+package com.massivecraft.massivecore.nms;
+
+import java.lang.reflect.Constructor;
+import org.bukkit.inventory.ItemStack;
+
+import com.massivecraft.massivecore.particleeffect.ReflectionUtils.PackageType;
+import com.massivecraft.massivecore.util.ReflectionUtil;
+
+public class NmsItemStack extends NmsAbstract
+{
+	// -------------------------------------------- //
+	// INSTANCE & CONSTRUCT
+	// -------------------------------------------- //
+	
+	private static NmsItemStack i = new NmsItemStack();
+	public static NmsItemStack get () { return i; }
+	
+	// -------------------------------------------- //
+	// FIELDS
+	// -------------------------------------------- //
+	
+	// net.minecraft.server.ItemStack
+	public Class<?> classNmsItemStack;
+	
+	// org.bukkit.craftbukkit.inventory.CraftItemStack
+	public Class<?> classCraftItemStack;
+	
+	// org.bukkit.craftbukkit.inventory.CraftItemStack(net.minecraft.server.ItemStack)
+	public Constructor<?> constructorCraftItemStack;
+	
+	// -------------------------------------------- //
+	// OVERRIDE
+	// -------------------------------------------- //
+	
+	// NOTE: This has been properly researched.
+	// NOTE: The constructor have been the same for quite some time! 
+	@Override
+	public int getRequiredVersion()
+	{
+		return 6;
+	}
+	
+	@Override
+	protected void setup() throws Throwable
+	{
+		this.classNmsItemStack = PackageType.MINECRAFT_SERVER.getClass("ItemStack");
+		this.classCraftItemStack = PackageType.CRAFTBUKKIT_INVENTORY.getClass("CraftItemStack");
+		this.constructorCraftItemStack = ReflectionUtil.getConstructor(this.classCraftItemStack, this.classNmsItemStack);
+	}
+	
+	// -------------------------------------------- //
+	// METHOD
+	// -------------------------------------------- //
+	
+	@SuppressWarnings("deprecation")
+	public ItemStack createItemStack()
+	{
+		// Create
+		ItemStack ret = null;
+		
+		// Fill
+		if (this.isAvailable())
+		{
+			ret = ReflectionUtil.invokeConstructor(this.constructorCraftItemStack, (Object[])null);
+		}
+		else
+		{
+			ret = new ItemStack(0);
+		}
+		
+		// Return
+		return ret;
+	}
+	
+}

src/com/massivecraft/massivecore/util/ReflectionUtil.java

@@ -31,6 +31,9 @@ public class ReflectionUtil
 		}
 	}
 	
+	private static final Class<?>[] EMPTY_ARRAY_OF_CLASS = {};
+	private static final Object[] EMPTY_ARRAY_OF_OBJECT = {};
+	
 	// -------------------------------------------- //
 	// MAKE ACCESSIBLE
 	// -------------------------------------------- //
@@ -96,7 +99,6 @@ public class ReflectionUtil
 		}
 	}
 	
-	private static final Class<?>[] EMPTY_ARRAY_OF_CLASS = {};
 	public static Method getMethod(Class<?> clazz, String name)
 	{
 		return getMethod(clazz, name, EMPTY_ARRAY_OF_CLASS);
@@ -115,13 +117,55 @@ public class ReflectionUtil
 		}
 	}
 	
-	private static final Object[] EMPTY_ARRAY_OF_OBJECT = {};
 	@SuppressWarnings("unchecked")
 	public static <T> T invokeMethod(Method method, Object target)
 	{
 		return (T) invokeMethod(method, target, EMPTY_ARRAY_OF_OBJECT);
 	}
 	
+	// -------------------------------------------- //
+	// CONSTRUCTOR
+	// -------------------------------------------- //
+	
+	@SuppressWarnings("unchecked")
+	public static <T> Constructor<T> getConstructor(Class<?> clazz, Class<?>... parameterTypes)
+	{
+		try
+		{
+			Constructor<T> ret = (Constructor<T>) clazz.getDeclaredConstructor(parameterTypes);
+			makeAccessible(ret);
+			return ret;
+		}
+		catch (Exception e)
+		{
+			throw asRuntimeException(e);
+		}
+	}
+	
+	public static <T> Constructor<T> getConstructor(Class<?> clazz)
+	{
+		return getConstructor(clazz, EMPTY_ARRAY_OF_CLASS);
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static <T> T invokeConstructor(Constructor<?> constructor, Object... arguments)
+	{
+		try
+		{
+			return (T) constructor.newInstance(arguments);
+		}
+		catch (Exception e)
+		{
+			throw asRuntimeException(e);
+		}
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static <T> T invokeConstructor(Constructor<?> constructor)
+	{
+		return (T) invokeConstructor(constructor, EMPTY_ARRAY_OF_OBJECT);
+	}
+	
 	// -------------------------------------------- //
 	// SINGLETON INSTANCE
 	// -------------------------------------------- //