Changed to Null ItemStack instead of null.

src/main/java/appeng/tile/AEBaseInvTile.java

@@ -111,7 +111,7 @@ public abstract class AEBaseInvTile extends AEBaseTile implements ISidedInventor
 	@Override
 	public ItemStack removeStackFromSlot( final int i )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

src/main/java/appeng/tile/AEBaseTile.java

@@ -110,7 +110,7 @@ public class AEBaseTile extends TileEntity implements IOrientable, ICommonTile,
 		final IStackSrc src = ITEM_STACKS.get( obj.getClass() );
 		if( src == null )
 		{
-			return null;
+			return ItemStack.EMPTY;
 		}
 		return src.stack( 1 );
 	}

src/main/java/appeng/tile/inventory/AppEngInternalAEInventory.java

@@ -174,13 +174,13 @@ public class AppEngInternalAEInventory implements IInventory, Iterable<ItemStack
 			return ns;
 		}
 
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override
 	public ItemStack removeStackFromSlot( final int var1 )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

src/main/java/appeng/tile/inventory/AppEngInternalInventory.java

@@ -99,7 +99,7 @@ public class AppEngInternalInventory implements IInventory, Iterable<ItemStack>
 			return ns;
 		}
 
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	protected boolean eventsEnabled()
@@ -110,7 +110,7 @@ public class AppEngInternalInventory implements IInventory, Iterable<ItemStack>
 	@Override
 	public ItemStack removeStackFromSlot( final int var1 )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

src/main/java/appeng/tile/inventory/AppEngNullInventory.java

@@ -46,19 +46,19 @@ public class AppEngNullInventory implements IInventory
 	@Override
 	public ItemStack getStackInSlot( final int var1 )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override
 	public ItemStack decrStackSize( final int slot, final int qty )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override
 	public ItemStack removeStackFromSlot( final int var1 )
 	{
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override

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

@@ -172,7 +172,7 @@ public class TileCondenser extends AEBaseInvTile implements IConfigManagerHost,
 
 			case TRASH:
 			default:
-				return null;
+				return ItemStack.EMPTY;
 		}
 	}
 
@@ -314,7 +314,7 @@ public class TileCondenser extends AEBaseInvTile implements IConfigManagerHost,
 		public ItemStack getStackInSlot( int slot )
 		{
 			// The void slot never has any content
-			return null;
+			return ItemStack.EMPTY;
 		}
 
 		@Override
@@ -328,13 +328,13 @@ public class TileCondenser extends AEBaseInvTile implements IConfigManagerHost,
 			{
 				addPower( stack.getCount() );
 			}
-			return null;
+			return ItemStack.EMPTY;
 		}
 
 		@Override
 		public ItemStack extractItem( int slot, int amount, boolean simulate )
 		{
-			return null;
+			return ItemStack.EMPTY;
 		}
 
 		@Override

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

@@ -672,7 +672,7 @@ public class TileInscriber extends AENetworkPowerTile implements IGridTickable,
 			{
 				return inv.getStackInSlot( extractSlot );
 			}
-			return null;
+			return ItemStack.EMPTY;
 		}
 
 		@Override
@@ -708,7 +708,7 @@ public class TileInscriber extends AENetworkPowerTile implements IGridTickable,
 
 			if( slot != validExtractSlot || amount == 0 )
 			{
-				return null;
+				return ItemStack.EMPTY;
 			}
 
 			AdaptorIInventory adapter = new AdaptorIInventory( new WrapperInventoryRange( TileInscriber.this, extractSlot, 1, true ) );

src/main/java/appeng/tile/powersink/TeslaEnergyAdapter.java

@@ -1,3 +1,21 @@
+/*
+ * This file is part of Applied Energistics 2.
+ * Copyright (c) 2013 - 2014, AlgorithmX2, All rights reserved.
+ *
+ * Applied Energistics 2 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Applied Energistics 2 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with Applied Energistics 2.  If not, see <http://www.gnu.org/licenses/lgpl>.
+ */
+
 package appeng.tile.powersink;
 
 

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

@@ -700,7 +700,7 @@ public class TileChest extends AENetworkPowerTile implements IMEChest, ITerminal
 		{
 			return this.storageType;
 		}
-		return null;
+		return ItemStack.EMPTY;
 	}
 
 	@Override