Your Block ID's (or, "Endermen and Your Blocks")

[intermediateuser]

If you're making custom blocks, it might be a good idea to consider what number range you're using for their ID's.  When an Enderman tries to pick up one of your blocks, it will check the block's ID (that you gave it) against an array of blocks it is allowed to carry.  The array itself has a set size of 256; if your ID's go beyond 255 127* (because 0 is one of the 256 indices), and an Enderman tries to pick up one of your blocks, the game will crash with an "index out of bounds" error.

 

It's a rare occurrence, of course; I just thought I'd mention it to help anybody who might be searching for a solution, or just starting out.

 

Happy code wrangling!

 

*Edit: As Draco pointed out below, the bug has been reported and it appears that the number you cannot go above is 127, rather than 255.  Still, here's hoping this helps someone out.

[Draco18s]

This is more appropriately a vanilla bug.

 

In fact it has already been reported

[LexManos]

https://github.com/MinecraftForge/MinecraftForge/blob/master/common/net/minecraftforge/common/MinecraftForge.java#L208

We fix that.