Link SMP Server: Arrow crash fix.

This is a quick patch fix for the Arrow crash bug in the Minecraft SMP server. The bug results in an error like:

[SEVERE] Unexpected exception
java.lang.NullPointerException
       at ll.o_(SourceFile:128)
       at dh.a(SourceFile:1160)
       at dn.a(SourceFile:43)
       at dh.g(SourceFile:1136)
       at dh.e(SourceFile:1115)
       at net.minecraft.server.MinecraftServer.h(SourceFile:374)
       at net.minecraft.server.MinecraftServer.run(SourceFile:307)
       at bo.run(SourceFile:422)

If you get this bug and your server crashes, it’s because someone fired an arrow into a burning block and the arrow is now sticking in mid-air. The server then crashes every time it loads the chunk with the stranded arrow.

The linked file contains a replacement ll.class. If you know how to replace your class files in minecraft, this new ll.class will check for stranded arrows thus avoiding the crash. If you’re standing close, and see the stranded arrows, your client will still crash, but by the time you reconnect the server will have dropped the arrows to the ground and all will be right with the world once again.