Vanilla class overwriting

[Rokuw]

That's pretty much it, i wanted to overwrite the sand block class with my own so that sand doesn't fall... I already know hot to stop its gravity, but how to "patch" the original class with my custom one is da thing

[Tslat]

Could look at something like this, though it's reasonably advanced

 

http://www.minecraftforum.net/forums/mapping-and-modding/mapping-and-modding-tutorials/1571568-tutorial-1-6-2-changing-vanilla-without-editing

[Elyon]

Reflection or ASM, depending on your specific needs and your desired cross-mod compatibility.

[Rokuw]

Yeah, well, i'm gonna try it, but 99% chance i'll stick with falling sand