I can't open Minecraft because it keeps crashing on me!

Log:
[16:02:26] [Client thread/INFO]: Setting user: DaEnderGeek
[16:02:27] [Client thread/INFO]: (Session ID is token:7b14f00ba3624e978edbf94d4f215a35:577a52f77875423e8fec8a7ee3e2a94b)
Exception in thread "Client thread" java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:213)
at com.google.common.collect.Lists$ReverseList.<init>(Lists.java:767)
at com.google.common.collect.Lists.reverse(Lists.java:759)
at lt.b(SourceFile:156)
at lt.<init>(SourceFile:43)
at net.minecraft.server.MinecraftServer.<init>(SourceFile:155)
at bpo.<init>(SourceFile:41)
at ave.<init>(SourceFile:293)
at net.minecraft.client.main.Main.main(SourceFile:124)