T E

I got almost the same exception couple times a second (untill it crashes), while playing normal multi player.

[17:08:57] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_40-ea]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_40-ea]
at h.a(SourceFile:61) [1.8.3.jar:?]
at avf.av(SourceFile:880) [1.8.3.jar:?]
at avf.a(SourceFile:325) [1.8.3.jar:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.3.jar:?]
Caused by: java.lang.NullPointerException
at bcz.a(SourceFile:301) ~[1.8.3.jar:?]
at fq.a(SourceFile:75) ~[1.8.3.jar:?]
at fq.a(SourceFile:16) ~[1.8.3.jar:?]
at fi$1.run(SourceFile:13) ~[1.8.3.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_40-ea]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_40-ea]
at h.a(SourceFile:60) ~[1.8.3.jar:?]
... 3 more
AL lib: (EE) alc_cleanup: 1 device not closed