[MC-64118] Overloaded worlds cause seperate crashs / errors

This should not be a duplicate of ~~MC-64117~~ as this report here describes all the resulting problems, bugs and crashes of a overloaded world while ~~MC-64117~~ describes the bug that you can open a Minecraft world twice with the same Minecraft instance

I hope this is not invalid or at least even when it is, it shows some small bugs in Minecraft when the game is overloaded.

When you open the world you will get first these messages:

[13:01:33 INFO]: Client> java.lang.Exception: Stack trace
[13:01:33 INFO]: Client> 	at java.lang.Thread.dumpStack(Unknown Source)
[13:01:33 INFO]: Client> 	at bed.a(SourceFile:641)
[13:01:33 INFO]: Client> 	at bet.a(SourceFile:333)
[13:01:33 INFO]: Client> 	at bet.a(SourceFile:95)
[13:01:33 INFO]: Client> 	at bet.a(SourceFile:83)
[13:01:33 INFO]: Client> 	at qk.e(SourceFile:133)
[13:01:33 INFO]: Client> 	at qk.c(SourceFile:85)
[13:01:33 INFO]: Client> 	at qj.<init>(SourceFile:39)
[13:01:33 INFO]: Client> 	at qi.a(SourceFile:231)
[13:01:33 INFO]: Client> 	at qi.d(SourceFile:370)
[13:01:33 INFO]: Client> 	at sf.d(SourceFile:285)
[13:01:33 INFO]: Client> 	at rb.a(SourceFile:313)
[13:01:33 INFO]: Client> 	at mc.a(SourceFile:126)
[13:01:33 INFO]: Client> 	at md.a(SourceFile:57)
[13:01:33 INFO]: Client> 	at ie.run(SourceFile:13)
[13:01:33 INFO]: Client> 	at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
[13:01:33 INFO]: Client> 	at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
[13:01:33 INFO]: Client> 	at java.util.concurrent.FutureTask.run(Unknown Source)
[13:01:33 INFO]: Client> 	at net.minecraft.server.MinecraftServer.y(SourceFile:574)
[13:01:33 INFO]: Client> 	at net.minecraft.server.MinecraftServer.x(SourceFile:529)
[13:01:33 INFO]: Client> 	at cwp.x(SourceFile:144)
[13:01:33 INFO]: Client> 	at net.minecraft.server.MinecraftServer.run(SourceFile:445)
[13:01:33 INFO]: Client> 	at java.lang.Thread.run(Unknown Source)
[13:01:43 INFO]: Client> [13:01:43] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:43 INFO]: Client> [13:01:43] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:44 INFO]: Client> [13:01:44] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:52 INFO]: Client> [13:01:52] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:52 INFO]: Client> [13:01:52] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:52 INFO]: Client> [13:01:52] [Server thread/WARN]: Fetching addPacket for removed entity
[13:01:52 INFO]: Client> [13:01:52] [Client thread/ERROR]: Item entity 27748 has no item?!


############################################################

[12:56:43 INFO]: Client> [12:56:43] [Server thread/ERROR]: Couldn't process command: 'execute @e ~ ~ ~ detect ~ ~-1 ~ tnt 0 /setblock ~ ~ ~ fire'
[12:56:43 INFO]: Client> java.lang.NullPointerException


############################################################

[12:56:39 INFO]: Client> [12:56:39] [Server thread/ERROR]: Couldn't process command: 'execute @e ~ ~ ~ detect ~ ~-1 ~ tnt 0 /setblock ~ ~ ~ fire'
[12:56:39 INFO]: Client> java.lang.NullPointerException
[12:56:39 INFO]: Client> 	at z.a(SourceFile:161) ~[14w30c.jar:?]
[12:56:39 INFO]: Client> 	at bk.b(SourceFile:43) ~[14w30c.jar:?]
[12:56:39 INFO]: Client> 	at ab.a(SourceFile:79) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at ab.a(SourceFile:55) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at apm.a(SourceFile:98) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at atr.c(SourceFile:53) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at ql.a(SourceFile:518) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at ql.c(SourceFile:199) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at net.minecraft.server.MinecraftServer.y(SourceFile:597) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at net.minecraft.server.MinecraftServer.x(SourceFile:529) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at cwp.x(SourceFile:144) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at net.minecraft.server.MinecraftServer.run(SourceFile:445) [14w30c.jar:?]
[12:56:39 INFO]: Client> 	at java.lang.Thread.run(Unknown Source) [?:1.6.0_45]

And then it could even happen that the world crashes