Fix facade recipes. Hopefully the last null check fix.

src/main/java/appeng/block/AEBaseTileBlock.java

@@ -34,6 +34,7 @@ import net.minecraft.block.state.BlockStateContainer;
 import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.init.Blocks;
 import net.minecraft.inventory.Container;
 import net.minecraft.inventory.IInventory;
 import net.minecraft.item.EnumDyeColor;
@@ -272,7 +273,7 @@ public abstract class AEBaseTileBlock extends AEBaseBlock implements ITileEntity
 	public boolean onBlockActivated( World world, BlockPos pos, IBlockState state, EntityPlayer player, EnumHand hand, EnumFacing facing, float hitX, float hitY, float hitZ )
 	{
 		ItemStack heldItem;
-		if( player != null && player.getHeldItemMainhand() != null )
+		if( player != null && !player.getHeldItemMainhand().isEmpty() )
 		{
 			heldItem = player.getHeldItemMainhand();
 			

src/main/java/appeng/block/networking/BlockCableBus.java

@@ -257,7 +257,7 @@ public class BlockCableBus extends AEBaseTileBlock
 		// Our built-in model has the actual baked sprites we need
 		IBakedModel model = Minecraft.getMinecraft().getBlockRendererDispatcher().getModelForState( getDefaultState() );
 
-		// We cannot add the effect if we dont have the model
+		// We cannot add the effect if we don't have the model
 		if( !( model instanceof CableBusBakedModel ) )
 		{
 			return true;

src/main/java/appeng/client/ClientHelper.java

@@ -338,11 +338,11 @@ public class ClientHelper extends ServerHelper
 		if( player.isSneaking() )
 		{
 			final EnumHand hand;
-			if( player.getHeldItem( EnumHand.MAIN_HAND ) != null && player.getHeldItem( EnumHand.MAIN_HAND ).getItem() instanceof IMouseWheelItem )
+			if( !player.getHeldItem( EnumHand.MAIN_HAND ).isEmpty() && player.getHeldItem( EnumHand.MAIN_HAND ).getItem() instanceof IMouseWheelItem )
 			{
 				hand = EnumHand.MAIN_HAND;
 			}
-			else if( player.getHeldItem( EnumHand.OFF_HAND ) != null && player.getHeldItem( EnumHand.OFF_HAND ).getItem() instanceof IMouseWheelItem )
+			else if( !player.getHeldItem( EnumHand.OFF_HAND ).isEmpty() && player.getHeldItem( EnumHand.OFF_HAND ).getItem() instanceof IMouseWheelItem )
 			{
 				hand = EnumHand.OFF_HAND;
 			}

src/main/java/appeng/client/render/TesrRenderHelper.java

@@ -99,7 +99,7 @@ public class TesrRenderHelper
 	 */
 	public static void renderItem2d( ItemStack itemStack, float scale )
 	{
-		if( itemStack != null )
+		if( !itemStack.isEmpty() )
 		{
 			OpenGlHelper.setLightmapTextureCoords( OpenGlHelper.lightmapTexUnit, 240.f, 240.0f );
 

src/main/java/appeng/client/render/tesr/InscriberTESR.java

@@ -1,6 +1,8 @@
 package appeng.client.render.tesr;
 
 
+import net.minecraft.init.Blocks;
+import net.minecraft.init.Items;
 import org.lwjgl.opengl.GL11;
 
 import net.minecraft.block.Block;
@@ -200,7 +202,7 @@ public class InscriberTESR extends TileEntitySpecialRenderer<TileInscriber>
 
 				// heuristic to scale items down much further than blocks
 				final Block blk = Block.getBlockFromItem( sis.getItem() );
-				if( blk == null )
+				if( blk == Blocks.AIR )
 				{
 					GlStateManager.scale( 0.5, 0.5, 0.5 );
 				}

src/main/java/appeng/container/implementations/ContainerInterfaceTerminal.java

@@ -430,7 +430,7 @@ public final class ContainerInterfaceTerminal extends AEBaseContainer
 		@Override
 		public boolean isItemValid( final ItemStack itemstack )
 		{
-			return itemstack != null && itemstack.getItem() instanceof ItemEncodedPattern;
+			return !itemstack.isEmpty() && itemstack.getItem() instanceof ItemEncodedPattern;
 		}
 	}
 }

src/main/java/appeng/container/implementations/ContainerNetworkStatus.java

@@ -24,6 +24,7 @@ import java.io.IOException;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.entity.player.EntityPlayerMP;
 import net.minecraft.entity.player.InventoryPlayer;
+import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 
 import appeng.api.AEApi;
@@ -118,7 +119,7 @@ public class ContainerNetworkStatus extends AEBaseContainer
 					{
 						final IGridBlock blk = machine.getGridBlock();
 						final ItemStack is = blk.getMachineRepresentation();
-						if( !is.isEmpty() && is.getItem() != null )
+						if( !is.isEmpty() && is.getItem() != Items.AIR )
 						{
 							final IAEItemStack ais = AEItemStack.create( is );
 							ais.setStackSize( 1 );

src/main/java/appeng/container/implementations/ContainerQuartzKnife.java

@@ -77,7 +77,7 @@ public class ContainerQuartzKnife extends AEBaseContainer implements IAEAppEngIn
 
 		if( currentItem != this.toolInv.getItemStack() )
 		{
-			if( currentItem != null )
+			if( !currentItem.isEmpty() )
 			{
 				if( Platform.itemComparisons().isEqualItem( this.toolInv.getItemStack(), currentItem ) )
 				{
@@ -173,7 +173,7 @@ public class ContainerQuartzKnife extends AEBaseContainer implements IAEAppEngIn
 
 			if( item.getCount() == 0 )
 			{
-				this.getPlayerInv().mainInventory.add( this.getPlayerInv().currentItem, null );
+				this.getPlayerInv().mainInventory.add( this.getPlayerInv().currentItem, ItemStack.EMPTY );
 				MinecraftForge.EVENT_BUS.post( new PlayerDestroyItemEvent( this.getPlayerInv().player, item, null ) );
 			}
 
@@ -191,7 +191,7 @@ public class ContainerQuartzKnife extends AEBaseContainer implements IAEAppEngIn
 	@Override
 	public void setInventorySlotContents( final int var1, final ItemStack var2 )
 	{
-		if( var2 == null && Platform.isServer() )
+		if( var2.isEmpty() && Platform.isServer() )
 		{
 			this.makePlate();
 		}

src/main/java/appeng/container/slot/SlotRestrictedInput.java

@@ -105,7 +105,7 @@ public class SlotRestrictedInput extends AppEngSlot
 		{
 			return false;
 		}
-		if( i.getItem() == null )
+		if( i.getItem() == Items.AIR )
 		{
 			return false;
 		}

src/main/java/appeng/core/FacadeConfig.java

@@ -25,6 +25,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import net.minecraft.block.Block;
+import net.minecraft.init.Blocks;
 import net.minecraft.item.Item;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.common.config.Configuration;

src/main/java/appeng/core/api/imc/IMCBlackListSpatial.java

@@ -20,6 +20,7 @@ package appeng.core.api.imc;
 
 
 import net.minecraft.block.Block;
+import net.minecraft.init.Blocks;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.fml.common.event.FMLInterModComms.IMCMessage;
 
@@ -39,7 +40,7 @@ public class IMCBlackListSpatial implements IIMCProcessor
 		if( !is.isEmpty() )
 		{
 			final Block blk = Block.getBlockFromItem( is.getItem() );
-			if( blk != null )
+			if( blk != Blocks.AIR )
 			{
 				AEApi.instance().registries().movable().blacklistBlock( blk );
 				return;

src/main/java/appeng/core/api/imc/IMCGrinder.java

@@ -75,12 +75,12 @@ public class IMCGrinder implements IIMCProcessor
 
 		final int turns = msg.getInteger( "turns" );
 
-		if( in == null )
+		if( in.isEmpty() )
 		{
 			throw new IllegalStateException( "invalid input" );
 		}
 
-		if( out == null )
+		if( out.isEmpty() )
 		{
 			throw new IllegalStateException( "invalid output" );
 		}
@@ -90,7 +90,7 @@ public class IMCGrinder implements IIMCProcessor
 			final NBTTagCompound optionalTag = (NBTTagCompound) msg.getTag( "optional" );
 			final ItemStack optional = new ItemStack( optionalTag );
 
-			if( optional == null )
+			if( optional.isEmpty() )
 			{
 				throw new IllegalStateException( "invalid optional" );
 			}

src/main/java/appeng/core/api/imc/IMCMatterCannon.java

@@ -52,7 +52,7 @@ public class IMCMatterCannon implements IIMCProcessor
 		final ItemStack ammo = new ItemStack( item );
 		final double weight = msg.getDouble( "weight" );
 
-		if( ammo == null )
+		if( ammo.isEmpty() )
 		{
 			throw new IllegalStateException( "invalid item in message " + m );
 		}

src/main/java/appeng/core/stats/AchievementCraftingHandler.java

@@ -44,7 +44,7 @@ public class AchievementCraftingHandler
 	@SubscribeEvent
 	public void onPlayerCraftingEvent( final PlayerEvent.ItemCraftedEvent event )
 	{
-		if( this.differentiator.isNoPlayer( event.player ) || event.crafting == null )
+		if( this.differentiator.isNoPlayer( event.player ) || event.crafting.isEmpty() )
 		{
 			return;
 		}

src/main/java/appeng/core/stats/AchievementPickupHandler.java

@@ -45,7 +45,7 @@ public class AchievementPickupHandler
 	@SubscribeEvent
 	public void onItemPickUp( final PlayerEvent.ItemPickupEvent event )
 	{
-		if( this.differentiator.isNoPlayer( event.player ) || event.pickedUp == null || event.pickedUp.getEntityItem() == null )
+		if( this.differentiator.isNoPlayer( event.player ) || event.pickedUp == null || event.pickedUp.getEntityItem().isEmpty() )
 		{
 			return;
 		}

src/main/java/appeng/core/stats/Achievements.java

@@ -116,7 +116,7 @@ public enum Achievements
 
 	Achievements( final int x, final int y, final AEColoredItemDefinition which, final AchievementType type )
 	{
-		this.stack = ( which != null ) ? which.stack( AEColor.TRANSPARENT, 1 ) : null;
+		this.stack = ( which != null ) ? which.stack( AEColor.TRANSPARENT, 1 ) : ItemStack.EMPTY;
 		this.type = type;
 		this.x = x;
 		this.y = y;
@@ -145,7 +145,7 @@ public enum Achievements
 
 	public Achievement getAchievement()
 	{
-		if( this.stat == null && this.getStack() != null )
+		if( this.stat == null && !this.getStack().isEmpty() )
 		{
 			this.stat = new Achievement( "achievement.ae2." + this.name(), "ae2." + this.name(), this.x, this.y, this.getStack(), this.parent );
 			this.stat.registerStat();

src/main/java/appeng/core/sync/packets/PacketValueConfig.java

@@ -98,14 +98,14 @@ public class PacketValueConfig extends AppEngPacket
 	{
 		final Container c = player.openContainer;
 
-		if( this.Name.equals( "Item" ) && ( ( player.getHeldItem( EnumHand.MAIN_HAND ) != null && player.getHeldItem(EnumHand.MAIN_HAND).getItem() instanceof IMouseWheelItem ) || ( player.getHeldItem( EnumHand.OFF_HAND ) != null && player.getHeldItem(EnumHand.OFF_HAND).getItem() instanceof IMouseWheelItem ) ) )
+		if( this.Name.equals( "Item" ) && ( ( !player.getHeldItem( EnumHand.MAIN_HAND ).isEmpty() && player.getHeldItem(EnumHand.MAIN_HAND).getItem() instanceof IMouseWheelItem ) || ( !player.getHeldItem( EnumHand.OFF_HAND ).isEmpty() && player.getHeldItem(EnumHand.OFF_HAND).getItem() instanceof IMouseWheelItem ) ) )
 		{
 			final EnumHand hand;
-			if( player.getHeldItem( EnumHand.MAIN_HAND ) != null && player.getHeldItem( EnumHand.MAIN_HAND ).getItem() instanceof IMouseWheelItem )
+			if( !player.getHeldItem( EnumHand.MAIN_HAND ).isEmpty() && player.getHeldItem( EnumHand.MAIN_HAND ).getItem() instanceof IMouseWheelItem )
 			{
 				hand = EnumHand.MAIN_HAND;
 			}
-			else if( player.getHeldItem( EnumHand.OFF_HAND ) != null && player.getHeldItem( EnumHand.OFF_HAND ).getItem() instanceof IMouseWheelItem )
+			else if( !player.getHeldItem( EnumHand.OFF_HAND ).isEmpty() && player.getHeldItem( EnumHand.OFF_HAND ).getItem() instanceof IMouseWheelItem )
 			{
 				hand = EnumHand.OFF_HAND;
 			}

src/main/java/appeng/decorative/solid/BlockSkyStone.java

@@ -21,6 +21,7 @@ package appeng.decorative.solid;
 
 import net.minecraft.block.material.Material;
 import net.minecraft.block.state.IBlockState;
+import net.minecraft.init.Items;
 import net.minecraft.inventory.EntityEquipmentSlot;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.math.BlockPos;
@@ -64,7 +65,7 @@ public class BlockSkyStone extends AEBaseBlock
 			final ItemStack is = event.getEntityPlayer().getItemStackFromSlot( EntityEquipmentSlot.MAINHAND );
 			int level = -1;
 
-			if( !is.isEmpty() && is.getItem() != null )
+			if( !is.isEmpty() && is.getItem() != Items.AIR )
 			{
 				level = is.getItem().getHarvestLevel( is, "pickaxe", event.getEntityPlayer(), event.getState() );
 			}

src/main/java/appeng/entity/EntityChargedQuartz.java

@@ -119,7 +119,7 @@ public final class EntityChargedQuartz extends AEBaseEntityItem
 				if( e instanceof EntityItem && !e.isDead )
 				{
 					final ItemStack other = ( (EntityItem) e ).getEntityItem();
-					if( other != null && other.getCount() > 0 )
+					if( !other.isEmpty() && other.getCount() > 0 )
 					{
 						if( Platform.itemComparisons().isEqualItem( other, new ItemStack( Items.REDSTONE ) ) )
 						{

src/main/java/appeng/entity/EntitySingularity.java

@@ -93,7 +93,7 @@ public final class EntitySingularity extends AEBaseEntityItem
 				if( e instanceof EntityItem )
 				{
 					final ItemStack other = ( (EntityItem) e ).getEntityItem();
-					if( other != null )
+					if( !other.isEmpty() )
 					{
 						boolean matches = false;
 						for( final ItemStack is : OreDictionary.getOres( "dustEnder" ) )

src/main/java/appeng/entity/EntityTinyTNTPrimed.java

@@ -29,6 +29,7 @@ import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.MoverType;
 import net.minecraft.entity.item.EntityItem;
 import net.minecraft.entity.item.EntityTNTPrimed;
+import net.minecraft.init.Blocks;
 import net.minecraft.init.SoundEvents;
 import net.minecraft.util.DamageSource;
 import net.minecraft.util.EnumParticleTypes;

src/main/java/appeng/facade/FacadePart.java

@@ -25,6 +25,7 @@ import net.minecraft.block.state.IBlockState;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.init.Blocks;
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 
@@ -90,7 +91,7 @@ public class FacadePart implements IFacadePart, IBoxProvider
 		final ItemStack is = this.getTextureItem();
 		if( is.isEmpty() )
 		{
-			return null;
+			return Items.AIR;
 		}
 		return is.getItem();
 	}
@@ -123,7 +124,6 @@ public class FacadePart implements IFacadePart, IBoxProvider
 		return this.getBlockState().isOpaqueCube();
 	}
 
-	@Nullable
 	@Override
 	public ItemStack getTextureItem()
 	{
@@ -137,7 +137,7 @@ public class FacadePart implements IFacadePart, IBoxProvider
 			return facade.getTextureItem( this.facade );
 		}
 
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

src/main/java/appeng/helpers/DualityInterface.java

@@ -32,6 +32,7 @@ import com.google.common.collect.ImmutableSet;
 
 import net.minecraft.block.Block;
 import net.minecraft.block.state.IBlockState;
+import net.minecraft.init.Items;
 import net.minecraft.inventory.IInventory;
 import net.minecraft.inventory.ISidedInventory;
 import net.minecraft.inventory.InventoryCrafting;
@@ -1225,13 +1226,13 @@ public class DualityInterface implements IGridTickable, IStorageMonitorable, IIn
 					BAD_BLOCKS.add( directedBlock ); // nope!
 				}
 
-				if( what.getItem() != null )
+				if( what.getItem() != Items.AIR )
 				{
 					return what.getUnlocalizedName();
 				}
 
 				final Item item = Item.getItemFromBlock( directedBlock );
-				if( item == null )
+				if( item == Items.AIR )
 				{
 					return directedBlock.getUnlocalizedName();
 				}

src/main/java/appeng/helpers/PatternHelper.java

@@ -89,7 +89,7 @@ public class PatternHelper implements ICraftingPatternDetails, Comparable<Patter
 
 			this.crafting.setInventorySlotContents( x, gs );
 
-			if( gs != null && ( !this.isCrafting || !gs.hasTagCompound() ) )
+			if( !gs.isEmpty() && ( !this.isCrafting || !gs.hasTagCompound() ) )
 			{
 				this.markItemAs( x, gs, TestStatus.ACCEPT );
 			}
@@ -121,7 +121,7 @@ public class PatternHelper implements ICraftingPatternDetails, Comparable<Patter
 			{
 				final ItemStack gs = new ItemStack( outTag.getCompoundTagAt( x ) );
 
-				if( gs != null )
+				if( !gs.isEmpty() )
 				{
 					out.add( AEApi.instance().storage().createItemStack( gs ) );
 				}
@@ -330,7 +330,7 @@ public class PatternHelper implements ICraftingPatternDetails, Comparable<Patter
 
 	private TestStatus getStatus( final int slotIndex, final ItemStack i )
 	{
-		if( this.crafting.getStackInSlot( slotIndex ) == null )
+		if( this.crafting.getStackInSlot( slotIndex ).isEmpty() )
 		{
 			return i == null ? TestStatus.ACCEPT : TestStatus.DECLINE;
 		}

src/main/java/appeng/integration/modules/jei/FacadeRegistryPlugin.java

@@ -66,7 +66,7 @@ class FacadeRegistryPlugin implements IRecipeRegistryPlugin
 			// Looking up if a certain block can be used to make a facade
 			ItemStack itemStack = (ItemStack) focus.getValue();
 
-			if( itemFacade.createFacadeForItem( itemStack, true ) != null )
+			if( !itemFacade.createFacadeForItem( itemStack, true ).isEmpty() )
 			{
 				return Collections.singletonList( VanillaRecipeCategoryUid.CRAFTING );
 			}
@@ -102,7 +102,7 @@ class FacadeRegistryPlugin implements IRecipeRegistryPlugin
 			ItemStack itemStack = (ItemStack) focus.getValue();
 			ItemStack facade = itemFacade.createFacadeForItem( itemStack, false );
 
-			if( facade != null )
+			if( !facade.isEmpty() )
 			{
 				return Collections.singletonList( (T) new FacadeRecipeWrapper( itemStack, cableAnchor, facade ) );
 			}

src/main/java/appeng/integration/modules/theoneprobe/tile/ChargerInfoProvider.java

@@ -46,7 +46,7 @@ public class ChargerInfoProvider implements ITileProbInfoProvider
 			final IInventory chargerInventory = charger.getInternalInventory();
 			final ItemStack chargingItem = chargerInventory.getStackInSlot( 0 );
 
-			if( chargingItem != null )
+			if( !chargingItem.isEmpty() )
 			{
 				final String currentInventory = chargingItem.getDisplayName();
 				final IProbeInfo centerAlignedHorizontalLayout = probeInfo

src/main/java/appeng/items/materials/ItemMaterial.java

@@ -37,6 +37,7 @@ import net.minecraft.creativetab.CreativeTabs;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.item.EntityItem;
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.init.Items;
 import net.minecraft.inventory.IInventory;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
@@ -220,7 +221,7 @@ public final class ItemMaterial extends AEBaseItem implements IStorageComponent,
 					{
 						for( final ItemStack is : options )
 						{
-							if( !is.isEmpty() && is.getItem() != null )
+							if( !is.isEmpty() && is.getItem() != Items.AIR )
 							{
 								replacement = is.copy();
 								break;

src/main/java/appeng/items/parts/ItemFacade.java

@@ -81,7 +81,7 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 		try
 		{
 			final ItemStack in = this.getTextureItem( is );
-			if( in != null )
+			if( !in.isEmpty() )
 			{
 				return super.getItemStackDisplayName( is ) + " - " + in.getDisplayName();
 			}
@@ -112,7 +112,7 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 				try
 				{
 					final Item item = Item.getItemFromBlock( b );
-					if( item == null )
+					if( item == Items.AIR )
 					{
 						continue;
 					}
@@ -122,7 +122,7 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 					for( final ItemStack l : tmpList )
 					{
 						final ItemStack facade = this.createFacadeForItem( l, false );
-						if( facade != null )
+						if( !facade.isEmpty() )
 						{
 							this.subTypes.add( facade );
 						}
@@ -153,13 +153,13 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 
 	public ItemStack createFacadeForItem( final ItemStack l, final boolean returnItem )
 	{
-		if( l == null )
+		if( l.isEmpty() )
 		{
 			return ItemStack.EMPTY;
 		}
 
 		final Block b = Block.getBlockFromItem( l.getItem() );
-		if( b == null || l.hasTagCompound() )
+		if( b == Blocks.AIR || l.hasTagCompound() )
 		{
 			return ItemStack.EMPTY;
 		}
@@ -205,7 +205,7 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 	public FacadePart createPartFromItemStack( final ItemStack is, final AEPartLocation side )
 	{
 		final ItemStack in = this.getTextureItem( is );
-		if( in != null )
+		if( !in.isEmpty() )
 		{
 			return new FacadePart( is, side );
 		}
@@ -265,14 +265,14 @@ public class ItemFacade extends AEBaseItem implements IFacadeItem, IAlphaPassIte
 
 		ItemStack baseItemStack = getTextureItem( is );
 
-		if( baseItemStack == null )
+		if( baseItemStack.isEmpty() )
 		{
 			return Blocks.GLASS.getDefaultState();
 		}
 
 		Block block = Block.getBlockFromItem( baseItemStack.getItem() );
 
-		if( block == null )
+		if( block == Blocks.AIR )
 		{
 			return Blocks.GLASS.getDefaultState();
 		}

src/main/java/appeng/items/tools/powered/ToolColorApplicator.java

@@ -243,7 +243,7 @@ public class ToolColorApplicator extends AEBasePoweredItem implements IStorageCe
 		{
 			final NBTTagCompound color = c.getCompoundTag( "color" );
 			final ItemStack oldColor = new ItemStack( color );
-			if( oldColor != null )
+			if( !oldColor.isEmpty() )
 			{
 				return oldColor;
 			}

src/main/java/appeng/items/tools/powered/ToolEntropyManipulator.java

@@ -289,7 +289,7 @@ public class ToolEntropyManipulator extends AEBasePoweredItem implements IBlockT
 				{
 					final ItemStack result = FurnaceRecipes.instance().getSmeltingResult( i );
 
-					if( result != null )
+					if( !result.isEmpty() )
 					{
 						if( result.getItem() instanceof ItemBlock )
 						{

src/main/java/appeng/me/storage/CellInventory.java

@@ -462,7 +462,7 @@ public class CellInventory implements ICellInventory
 		try
 		{
 			t = new ItemStack( compoundTag );
-			if( t == null )
+			if( t.isEmpty() )
 			{
 				AELog.warn( "Removing item " + compoundTag + " from storage cell because the associated item type couldn't be found." );
 				return;

src/main/java/appeng/parts/AEBasePart.java

@@ -426,7 +426,7 @@ public abstract class AEBasePart implements IPart, IGridProxyable, IActionHost,
 	{
 		final ItemStack memCardIS = player.inventory.getCurrentItem();
 
-		if( memCardIS != null && this.useStandardMemoryCard() && memCardIS.getItem() instanceof IMemoryCard )
+		if( !memCardIS.isEmpty() && this.useStandardMemoryCard() && memCardIS.getItem() instanceof IMemoryCard )
 		{
 			final IMemoryCard memoryCard = (IMemoryCard) memCardIS.getItem();
 

src/main/java/appeng/parts/PartPlacement.java

@@ -436,7 +436,7 @@ public class PartPlacement
 				boolean supportedItem = items.memoryCard().isSameAs( held );
 				supportedItem |= items.colorApplicator().isSameAs( held );
 
-				if( event.getEntityPlayer().isSneaking() && held != null && supportedItem )
+				if( event.getEntityPlayer().isSneaking() && !held.isEmpty() && supportedItem )
 				{
 					NetworkHandler.instance().sendToServer( new PacketClick( event.getPos(), event.getFace(), 0, 0, 0, event.getHand() ) );
 				}

src/main/java/appeng/parts/automation/PartIdentityAnnihilationPlane.java

@@ -23,6 +23,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import net.minecraft.block.state.IBlockState;
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.tileentity.TileEntity;
@@ -86,7 +87,7 @@ public class PartIdentityAnnihilationPlane extends PartAnnihilationPlane
 			final List<ItemStack> out = new ArrayList<ItemStack>( 1 );
 			final Item item = Item.getItemFromBlock( state.getBlock() );
 
-			if( item != null )
+			if( item != Items.AIR )
 			{
 				int meta = 0;
 				if( item.getHasSubtypes() )

src/main/java/appeng/parts/automation/PartImportBus.java

@@ -20,6 +20,7 @@ package appeng.parts.automation;
 
 
 import net.minecraft.entity.player.EntityPlayer;
+import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 import net.minecraft.util.EnumHand;
 import net.minecraft.util.ResourceLocation;
@@ -88,7 +89,7 @@ public class PartImportBus extends PartSharedItemBus implements IInventoryDestin
 	@Override
 	public boolean canInsert( final ItemStack stack )
 	{
-		if( stack.isEmpty() || stack.getItem() == null )
+		if( stack.isEmpty() || stack.getItem() == Items.AIR )
 		{
 			return false;
 		}

src/main/java/appeng/parts/automation/UpgradeInventory.java

@@ -19,6 +19,7 @@
 package appeng.parts.automation;
 
 
+import net.minecraft.init.Items;
 import net.minecraft.inventory.IInventory;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
@@ -117,7 +118,7 @@ public abstract class UpgradeInventory extends AppEngInternalInventory implement
 
 		for( final ItemStack is : this )
 		{
-			if( is == null || is.getItem() == null || !( is.getItem() instanceof IUpgradeModule ) )
+			if( is == null || is.getItem() == Items.AIR || !( is.getItem() instanceof IUpgradeModule ) )
 			{
 				continue;
 			}

src/main/java/appeng/parts/reporting/PartConversionMonitor.java

@@ -91,13 +91,13 @@ public class PartConversionMonitor extends AbstractPartMonitor
 		boolean ModeB = false;
 
 		ItemStack item = player.getHeldItem( hand );
-		if( item == null && this.getDisplayed() != null )
+		if( item.isEmpty() && this.getDisplayed() != null )
 		{
 			ModeB = true;
 			item = ( (IAEItemStack) this.getDisplayed() ).getItemStack();
 		}
 
-		if( item != null )
+		if( !item.isEmpty() )
 		{
 			try
 			{

src/main/java/appeng/recipes/Ingredient.java

@@ -24,6 +24,7 @@ import java.util.List;
 import com.google.common.base.Preconditions;
 
 import net.minecraft.block.Block;
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
@@ -167,7 +168,7 @@ public class Ingredient implements IIngredient
 		if( blk != null )
 		{
 			final Item it = Item.getItemFromBlock( blk );
-			if( it != null )
+			if( it != Items.AIR )
 			{
 				return this.makeItemStack( it, this.qty, this.meta, this.nbt );
 			}

src/main/java/appeng/recipes/game/DisassembleRecipe.java

@@ -78,7 +78,7 @@ public final class DisassembleRecipe implements IRecipe
 	@Override
 	public boolean matches( final InventoryCrafting inv, final World w )
 	{
-		return this.getOutput( inv ) != null;
+		return !this.getOutput( inv ).isEmpty();
 	}
 
 	@Nullable
@@ -111,7 +111,7 @@ public final class DisassembleRecipe implements IRecipe
 						final IItemList<IAEItemStack> list = cellInv.getAvailableItems( StorageChannel.ITEMS.createList() );
 						if( !list.isEmpty() )
 						{
-							return null;
+							return ItemStack.EMPTY;
 						}
 					}
 

src/main/java/appeng/recipes/game/FacadeRecipe.java

@@ -51,7 +51,7 @@ public final class FacadeRecipe implements IRecipe
 	@Override
 	public boolean matches( final InventoryCrafting inv, final World w )
 	{
-		return this.getOutput( inv, false ) != null;
+		return !this.getOutput( inv, false ).isEmpty();
 	}
 
 	@Nullable
@@ -62,7 +62,7 @@ public final class FacadeRecipe implements IRecipe
 			if( this.anchor.isSameAs( inv.getStackInSlot( 1 ) ) && this.anchor.isSameAs( inv.getStackInSlot( 3 ) ) && this.anchor.isSameAs( inv.getStackInSlot( 5 ) ) && this.anchor.isSameAs( inv.getStackInSlot( 7 ) ) )
 			{
 				final ItemStack facades = facade.createFacadeForItem( inv.getStackInSlot( 4 ), !createFacade );
-				if( facades != null && createFacade )
+				if( !facades.isEmpty() && createFacade )
 				{
 					facades.setCount( 4 );
 				}
@@ -70,7 +70,7 @@ public final class FacadeRecipe implements IRecipe
 			}
 		}
 
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

src/main/java/appeng/recipes/handlers/Smelt.java

@@ -21,6 +21,7 @@ package appeng.recipes.handlers;
 
 import java.util.List;
 
+import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 import net.minecraftforge.fml.common.registry.GameRegistry;
 
@@ -59,12 +60,12 @@ public class Smelt implements ICraftHandler, IWebsiteSerializer
 	@Override
 	public void register() throws RegistrationError, MissingIngredientError
 	{
-		if( this.in.getItemStack().getItem() == null )
+		if( this.in.getItemStack().getItem() == Items.AIR )
 		{
 			throw new RegistrationError( this.in.toString() + ": Smelting Input is not a valid item." );
 		}
 
-		if( this.out.getItemStack().getItem() == null )
+		if( this.out.getItemStack().getItem() == Items.AIR )
 		{
 			throw new RegistrationError( this.out.toString() + ": Smelting Output is not a valid item." );
 		}

src/main/java/appeng/recipes/ores/OreDictionaryHandler.java

@@ -43,7 +43,7 @@ public class OreDictionaryHandler
 	@SubscribeEvent
 	public void onOreDictionaryRegister( final OreDictionary.OreRegisterEvent event )
 	{
-		if( event.getName() == null || event.getOre() == null )
+		if( event.getName() == null || event.getOre().isEmpty() )
 		{
 			return;
 		}
@@ -111,7 +111,7 @@ public class OreDictionaryHandler
 			{
 				for( final ItemStack item : OreDictionary.getOres( name ) )
 				{
-					if( item != null )
+					if( !item.isEmpty() )
 					{
 						n.oreRegistered( name, item );
 					}

src/main/java/appeng/services/export/MinecraftItemCSVExporter.java

@@ -172,7 +172,7 @@ final class MinecraftItemCSVExporter implements Exporter
 				final Item item = input.getItem();
 				final String unlocalizedItem = input.getUnlocalizedName();
 				final Block block = Block.getBlockFromItem( item );
-				final boolean isBlock = block != null && !block.equals( Blocks.AIR );
+				final boolean isBlock = block != Blocks.AIR && !block.equals( Blocks.AIR );
 				final Class<? extends ItemStack> stackClass = input.getClass();
 				final String stackClassName = stackClass.getName();
 
@@ -275,7 +275,7 @@ final class MinecraftItemCSVExporter implements Exporter
 			if( this.mode == ExportMode.VERBOSE )
 			{
 				final Block block = Block.getBlockFromItem( input );
-				final boolean isBlock = block != null && !block.equals( Blocks.AIR );
+				final boolean isBlock = block != Blocks.AIR && !block.equals( Blocks.AIR );
 				final Class<? extends Item> itemClass = input.getClass();
 				final String itemClassName = itemClass.getName();
 

src/main/java/appeng/tile/misc/TileVibrationChamber.java

@@ -254,9 +254,9 @@ public class TileVibrationChamber extends AENetworkInvTile implements IGridTicka
 				is.grow( -1 );
 				if( is.getCount() <= 0 )
 				{
-					ItemStack container = null;
+					ItemStack container = ItemStack.EMPTY;
 
-					if( is.getItem() != null && is.getItem().hasContainerItem( is ) )
+					if( is.getItem() != Items.AIR && is.getItem().hasContainerItem( is ) )
 					{
 						container = is.getItem().getContainerItem( is );
 					}

src/main/java/appeng/tile/storage/TileDrive.java

@@ -265,7 +265,7 @@ public class TileDrive extends AENetworkInvTile implements IChestOrDrive, IPrior
 	@Override
 	public boolean isItemValidForSlot( final int i, final ItemStack itemstack )
 	{
-		return itemstack != null && AEApi.instance().registries().cell().isCellHandled( itemstack );
+		return !itemstack.isEmpty() && AEApi.instance().registries().cell().isCellHandled( itemstack );
 	}
 
 	@Override

src/main/java/appeng/util/InWorldToolOperationResult.java

@@ -58,7 +58,7 @@ public class InWorldToolOperationResult
 
 		for( final ItemStack l : items )
 		{
-			if( b == null )
+			if( b.isEmpty() )
 			{
 				final Block bl = Block.getBlockFromItem( l.getItem() );
 

src/main/java/appeng/util/Platform.java

@@ -681,7 +681,7 @@ public class Platform
 			return new ArrayList();
 		}
 
-		ItemStack itemStack = null;
+		ItemStack itemStack = ItemStack.EMPTY;
 		if( o instanceof AEItemStack )
 		{
 			final AEItemStack ais = (AEItemStack) o;
@@ -724,7 +724,7 @@ public class Platform
 			return "** Null";
 		}
 
-		ItemStack itemStack = null;
+		ItemStack itemStack = ItemStack.EMPTY;
 		if( o instanceof AEItemStack )
 		{
 			final String n = ( (AEItemStack) o ).getDisplayName();

src/main/java/appeng/util/helpers/ItemComparisonHelper.java

@@ -26,6 +26,7 @@ import java.util.Set;
 
 import javax.annotation.Nullable;
 
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTBase;
@@ -140,7 +141,7 @@ public class ItemComparisonHelper
 		 */
 
 		// test damageable items..
-		if( a.getItem() != null && b.getItem() != null && a.getItem().isDamageable() && a.getItem() == b.getItem() )
+		if( a.getItem() != Items.AIR && b.getItem() != Items.AIR && a.getItem().isDamageable() && a.getItem() == b.getItem() )
 		{
 			try
 			{
@@ -379,11 +380,11 @@ public class ItemComparisonHelper
 	 */
 	private boolean hasSameNbtTag( final ItemStack a, final ItemStack b )
 	{
-		if( a == null && b == null )
+		if( a.isEmpty() && b.isEmpty() )
 		{
 			return true;
 		}
-		if( a == null || b == null )
+		if( a.isEmpty() || b.isEmpty() )
 		{
 			return false;
 		}

src/main/java/appeng/util/item/AEItemStack.java

@@ -31,6 +31,7 @@ import javax.annotation.Nullable;
 
 import io.netty.buffer.ByteBuf;
 
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.CompressedStreamTools;
@@ -68,14 +69,14 @@ public final class AEItemStack extends AEStack<IAEItemStack> implements IAEItemS
 		}
 
 		final Item item = is.getItem();
-		if( item == null )
+		if( item == Items.AIR )
 		{
 			throw new InvalidParameterException( "Contained item is null, thus not a valid ItemStack for AEItemStack." );
 		}
 
 		this.setDefinition( new AEItemDef( item ) );
 
-		if( this.getDefinition().getItem() == null )
+		if( this.getDefinition().getItem() == Items.AIR )
 		{
 			throw new InvalidParameterException( "This ItemStack is bad, it has a null item." );
 		}

src/main/java/appeng/util/item/AESharedNBT.java

@@ -22,6 +22,7 @@ package appeng.util.item;
 import java.lang.ref.WeakReference;
 import java.util.WeakHashMap;
 
+import net.minecraft.init.Items;
 import net.minecraft.item.Item;
 import net.minecraft.item.ItemStack;
 import net.minecraft.nbt.NBTTagCompound;
@@ -81,7 +82,7 @@ public class AESharedNBT extends NBTTagCompound implements IAETagCompound
 
 		final Item item = s.getItem();
 		int meta = -1;
-		if( s.getItem() != null && s.isItemStackDamageable() && s.getHasSubtypes() )
+		if( s.getItem() != Items.AIR && s.isItemStackDamageable() && s.getHasSubtypes() )
 		{
 			meta = s.getItemDamage();
 		}

src/main/java/appeng/util/item/OreReference.java

@@ -26,6 +26,7 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
 
+import net.minecraft.init.Items;
 import net.minecraft.item.ItemStack;
 
 import appeng.api.storage.data.IAEItemStack;
@@ -54,7 +55,7 @@ public class OreReference
 			{
 				for( final ItemStack is : OreHelper.INSTANCE.getCachedOres( oreName ) )
 				{
-					if( is.getItem() != null )
+					if( is.getItem() != Items.AIR )
 					{
 						this.aeOtherOptions.add( AEItemStack.create( is ) );
 					}