Replaced all instances of Guava's Optional type with Java 8's Optional type, as discussed in #81. (#90)

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

@@ -153,12 +153,12 @@ public final class EntityChargedQuartz extends AEBaseEntityItem
 					netherQuartz.setDead();
 				}
 
-				for( final ItemStack fluixCrystalStack : materials.fluixCrystal().maybeStack( 2 ).asSet() )
+				materials.fluixCrystal().maybeStack( 2 ).ifPresent( is ->
 				{
-					final EntityItem entity = new EntityItem( this.worldObj, this.posX, this.posY, this.posZ, fluixCrystalStack );
+					final EntityItem entity = new EntityItem( this.worldObj, this.posX, this.posY, this.posZ, is );
 
 					this.worldObj.spawnEntityInWorld( entity );
-				}
+				} );
 
 				return true;
 			}

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

@@ -128,7 +128,7 @@ public final class EntitySingularity extends AEBaseEntityItem
 									e.setDead();
 								}
 
-								for( final ItemStack singularityStack : materials.qESingularity().maybeStack( 2 ).asSet() )
+								materials.qESingularity().maybeStack( 2 ).ifPresent( singularityStack ->
 								{
 									final NBTTagCompound cmp = Platform.openNbtData( singularityStack );
 									cmp.setLong( "freq", ( new Date() ).getTime() * 100 + ( randTickSeed ) % 100 );
@@ -137,7 +137,7 @@ public final class EntitySingularity extends AEBaseEntityItem
 
 									final EntitySingularity entity = new EntitySingularity( this.worldObj, this.posX, this.posY, this.posZ, singularityStack );
 									this.worldObj.spawnEntityInWorld( entity );
-								}
+								} );
 							}
 
 							if( item.stackSize <= 0 )

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

@@ -29,7 +29,6 @@ import net.minecraft.entity.EntityLivingBase;
 import net.minecraft.entity.item.EntityItem;
 import net.minecraft.entity.item.EntityTNTPrimed;
 import net.minecraft.init.SoundEvents;
-import net.minecraft.item.ItemStack;
 import net.minecraft.util.DamageSource;
 import net.minecraft.util.EnumParticleTypes;
 import net.minecraft.util.SoundCategory;
@@ -90,7 +89,7 @@ public final class EntityTinyTNTPrimed extends EntityTNTPrimed implements IEntit
 
 		if( this.isInWater() && Platform.isServer() ) // put out the fuse.
 		{
-			for( final ItemStack tntStack : AEApi.instance().definitions().blocks().tinyTNT().maybeStack( 1 ).asSet() )
+			AEApi.instance().definitions().blocks().tinyTNT().maybeStack( 1 ).ifPresent( tntStack ->
 			{
 				final EntityItem item = new EntityItem( this.worldObj, this.posX, this.posY, this.posZ, tntStack );
 
@@ -103,7 +102,7 @@ public final class EntityTinyTNTPrimed extends EntityTNTPrimed implements IEntit
 
 				this.worldObj.spawnEntityInWorld( item );
 				this.setDead();
-			}
+			} );
 		}
 
 		if( this.getFuse() <= 0 )