Draco18s

Register a key handler Send a packet to the server Server gets the packet and modify's the item

Well the thing that looks null is an object of type ArrowEffect. Figure out why it is null. Which constructor are you calling, what's the default value, etc.

Null pointer errors are easy to fix. go to the line it indicates, look at it, figure out what objects could possibly be null, backtrace to figure out why.

And...what seems to be the problem?

Try recoding that line so it makes sense. You're checking for "foo is not equal to foo" which will always be false. When you change it to be bar instead, then you're checking "if bar is not equal to foo" which might be true and might be false. What are the lines inside that statement doing? When do you want them to happen?

So you're getting the current item stack.... And then doing nothing with it.... And instead, checking the current item versus an ID....

Changing what the flag is affects this line: if (flag != this.isInfusing()) { //essentially this line is "this.isInfusing() != this.isInfusing()" flag1 = true; CrypticInfuser.updateFurnaceBlockState(this.isInfusing(), this.worldObj, this.xCoord, this.yCoord, this.zCoord); } Sooo....

Exactly what it says on the tin. You didn't put anything into the variable and you're getting nothing out of it. What did you expect to happen? http://en.wikipedia.org/wiki/Garbage_in,_garbage_out

Garbage in, garbage out.

EntityItem objects are Entities and can be found when dropped by using world#entitiesInAABB(...) There are at least three different versions, you're going to want the one that takes a Class as a parameter and looks for Entities that subclass the passed type.

I never found a way to get access to the texture sheet when I was poking around with it (1.7.10). I gave up and used two-pass blocks.

this.getTextureName() And is that value ever set anywhere?

AFAIK, you'd need to have a two-pass block. And I'm not sure how those work in 1.8, due to the way icons are handled now. The first pass would supply the base texture ("stone") and the second pass would supply the overlay (the cracks).

No, actually it doesn't. All it does is change the block-above to being the top half of a door with the correct metadata. The next line, notifyBlocksOfNeighborChange , is what makes double-doors work.

I like that list. My company's website is full of nothing but ducks. Refuctored, hydra-code, ducks. Another one of our programs as at least one loch ness bug, another application has a loch ness bug we know exists but can't reproduce in-house because Apple and iOS 8.0.0/1/2 FUBARed the whole thing ("Of COURSE I upgraded my device to 8.2! What do you think I am, stupid?" "Our tracking code says you're still on 8.0.2, which is broken.")

I remember looking at it once and going "how the fuck does this even work?" I was never able to back-trace the parts that I understood (each segment) back to another piece I understood (the world generator). I wish you luck.

You do know what that one line does, right?

No, it's not. It means your method signature is wrong. You'd know this if you had the prerequisite programming knowledge prior to starting modding.

String F=""+state_entrada.getValue(FACING); if(F.contains("down")){ ... } My god. It's full of Strings. Not to mention static properties. Jesus.

Remove that line entirely.

A ConcurrentModificationException occurs when two different threads of a program try to modify the same array structure.

Did you put the @Override annotation on it? What does it say when you do?

Seeing as I can't figure out what the class is doing right now, I can't help you. Find/replace all the srg names with sane, human-readable ones, and I might help you.

No.

I'll tell you what I told someone else. Refactor all of those variable names so that they're readable. if (d12 * d12 + d13 * d13 + d14 * d14 < 1.0D && p_76484_1_.getBlock(k2, l2, i3).isReplaceableOreGen(p_76484_1_, k2, l2, i3, blockB)) Is a mess, I can't read it, you can't read it, no one can read it and figure out what it's doing.