[MC-74984] Client continues to connect to server after canceling on 'Connecting to server' screen

I am on one server and i can read the chat from both of them.

Steps to Reproduce:
1. I started Minecraft 1.8
2. I joined a multiplayer server and while it was loading to found out that i joined the wrong one (CubeKrowd)
3. While it was still loading i cancled
4. I clicked on the right server and joind a world where only a few things where and i was in spectator mode although I should have only been in creative. At that point i could read both chats.
5. I disconnected and logged back in and now the world was normal but still there where both chats

And even if i disconnect again the cubekrowd chat is still there. I tested going to a few different servers but the chat was always there.

When i restarted the game it was gone

Being connected to two servers at a time (MC-74984) can be exploited:

Illegal movement (e.g. "phasing" through blocks), to some extent
Item transfer when in Creative mode
X-ray

See https://www.youtube.com/watch?v=EEG_c3ycDg4

Related issues

is duplicated by

MC-75183 Multiple instances (different to double instances due to lag)

MC-76663 Connected to multiple servers simultaneously on the same client.

MC-77819 Returning To Server-list And Not Main Menu

MC-78448 Join Multiple Servers with ONE Client

MC-79627 Connecting to multiple servers at the same time

MC-80144 Loading two servers with one Minecraft instance.

MC-80226 Connecting to two servers at once

MC-81678 confusing chat

MC-87667 double clicking a server before joining a server results in minecraft attempting to connect to both servers

MC-90327 Playing on two servers at once

MC-93545 Join server multiple times on double click

MC-93790 Chat from one server shows on another

MC-94663 Attempting to join a server, canceling, connecting to another server cancelling then connecting to the first server, but ending up in the second server.

MC-95139 Client can connect to 2 servers at once

MC-96306 I am in 2 servers at a time

MC-96985 Client's server list can be lightly spammed and break joining servers

MC-100686 Client can connect to multiple servers at once

MC-103846 Summary Connected to local and external server at the same

MC-103951 Multiplayer login issue

MC-108646 Connected to multiple servers at once

MC-113526 multiple people on a singleplayer world without lan

MC-116504 Canceling entry to a server does not work.

MC-120072 Server chat merges when connecting to another server

MC-121210 Connecting to 2 servers at the same time

MC-127677 Render Glitch changing servers

MC-129533 Server "combination" issues

MC-137115 In two servers at the same time

MC-151614 Game thinks I'm on a different world

MC-159329 Chat Bug

MC-168846 Canceling joining server and then joining singleplayer-world does wired stuff

MC-168999 2 servers merged into 1?

MC-176812 Pressing cancel when logging into a server does not cancel joining the server

MC-178732 I got into 2 minecraft servers at once

MC-186451 Inventory and map get carried over to a second server when rapidly switching servers

MC-189592 Cancel connection to the server, don't cancel it.

MC-192726 Joined to 2 servers at once

MC-193519 Collision breaks after canceling a connection to a multiplayer server, and joining a singleplayer world after

MC-194209 Minecraft Realms and Multiplayer Combination

MC-195177 Two worlds loading at once Xray bug

MC-199554 Singleplayer and Multiplayer Loading issue

MC-199622 weird server bug

MC-199683 The teleportation problem about joining the server

MC-201222 Online Server Chat loaded in Singleplayer

MC-210104 Trying to join a multiplayer server and cancelling right after, gives you the items inside of a singleplayer world.

MC-211372 Cancel joining a realm won't fully cancel the joining of the realm

MC-212019 1.16.5 Realms/Singleplayer bug

MC-212374 Connected to two servers at once

MC-214284 Killed on a Realm server while in a single player world

MC-217226 Joining servers too quickly causes your client to be in 2 servers at once.

MC-217487 It has been observed that one player is on multiple servers.

MC-218188 Aborting connection to a server quickly allows to connect to multiple servers

MC-220566 Joining server + realm at same time allows player to get effected by gamemode commands and fly on any server.

MC-221137 Multiplayer-singleplayer weird bug

MC-223001 Canceling a connection to a Realm causes desink between client and realm

MC-227783 Being connected to 2 servers at once.

REALMS-5531 After clicking on a realm and clicking cancel, sometimes it will send you to the realm while you are on the server select screen.

relates to

MC-12989 Chat from a server connected to using direct connect sometimes remains in chat when joining another server.

REALMS-5078 Realms "Cancel Join" button does not stop the client from joining the realm

MC-128953 Connection to server not closed after continuing after an OutOfMemory error

MC-78113 Disconnecting after death on hardcore mode server does not close connection to server

MC-88299 Client freezes then disconnects with java.io.IOException: Error while write(...) when trying to join a server

MC-124615 Overworld terrain generation in Nether

MC-133757 Day and Night Flash

REALMS-1178 Try to cancel loading a realm

Attachments

IMG_5051.mov

latest.log

Untitled video - Made with Clipchamp.mp4

Comments

migrated 2014-12-01T20:42:26Z

[media][media][media][media][media][media][media][media][media][media][media][media][media][media][media][media]

migrated 2014-12-01T21:18:54Z

ivalid, modded server, the chat and plots say it all

migrated 2014-12-01T21:29:15Z

The server i took thr pics on is a vanilla one....the plots were generated using commandblocks but you are right the chat is from cubekrowd

migrated 2014-12-01T21:40:36Z

IF the plots are made with command blocks, it is still invalid because of the chat messages
"Entering new CubeKrowd Lobby!"
and in front of the names: [M], [R], [T], [G]

migrated 2014-12-01T22:23:15Z

CubeKrowd is modded, you will need to contact them if you want any support on that server.

migrated 2015-02-20T22:43:26Z

Confirmed on vanilla.

migrated 2015-04-17T20:06:14Z

MC-78113 is related to/a duplicate of this one, but it contains a lot of information that might be useful.

migrated 2015-04-19T17:33:00Z

This is not a duplicate issue to mine reported at MC-78113 as my issue CAN NOT be created in clients below 1.8.3 unlike what is described here. Related maybe but not a duplicate.

migrated 2015-06-10T22:35:10Z

Here is a way of easy reproduction with any client and any server:

1. Increase your lookup-time for a servers DNS/IP (see start of the video)
(This can be done by using a proxyserver and forcing DNS-Lookups via the proxy)
2. Use "REFRESH" to mark all servers as "unknown" for a little while
3. Connect to two servers shortly after another.

Video:
https://www.youtube.com/watch?v=OpsrZB0x17I

Refreshing to show the resolve-latency
Connecting with a little delay (second connect 200ms later)
Visibly connection to two servers shortly after another
Flickering sky as one server has night and one has daytime
Commands upto 2015-06-11 00:18:13 are only registered on Server 1
"/chunk vd 5" forces a world-Change-Event with a 5-chunk viewdistance this forces a disconnect somehow from server 1
All additionall commands are registered by Server 2
TAB-Shows other players

Serverlog Server 1:

[2015-06-11 00:17:37 INFO]: Kademlia[5] logged in with entity id 5850 at ([world]920.5143804149387, 68.0, 2184.500539235966)
[2015-06-11 00:17:38 WARN]: Kademlia moved too quickly! -904.3122679052309,9.0,-1787.1306913904555 (904.3122679052309, 9.0, 1787.1306913904555)
[2015-06-11 00:17:52 INFO]: Kademlia issued server command: /v
[2015-06-11 00:17:54 INFO]: Kademlia issued server command: /lag
[2015-06-11 00:17:56 INFO]: Kademlia issued server command: /list
[2015-06-11 00:18:04 INFO]: Kademlia issued server command: /w spawn
[2015-06-11 00:18:13 INFO]: Kademlia issued server command: /chunk vd 5
[2015-06-11 00:18:16 INFO]: Saved 1 players in 1 MS.
[2015-06-11 00:19:01 INFO]: Kademlia lost connection: Disconnected

Serverlog Server 2:

2015-06-11 00:17:38] [Server thread/INFO]: Kademlia[1] logged in with entity id 5997165 at ([world]16.202112509707884, 77.0, 397.36984784551026)
[2015-06-11 00:18:14] [Server thread/WARN]: Kademlia moved too quickly! -126.60349590885434,-12.0,249.28627572675515 
[2015-06-11 00:18:25] [Server thread/INFO]: Kademlia issued server command: /chunk vd 15
[2015-06-11 00:18:40] [Server thread/INFO]: Kademlia issued server command: /w spawn

marcono1234 2015-06-21T12:43:29Z

Confirmed for

1.8.7 However I cannot reproduce it in the way @unknown did

How to reproduce:

Open server list
Press F5 until the servers are all marked as "pinging" and it stays like this for a while
Click on the "Play" arrow on one of the server images and press ESC at the same time (You should now be in the main menu of Minecraft)
Click "Multiplayer" and select any other server

Note: The client doesn't even cancel the updates when leaving the latest server and entering singleplayer but instead uses the same packages which causes the player to be teleported for example

Some error messages

java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
	at bcy.a(SourceFile:964) ~[1.8.7.jar:?]
	at gq.a(SourceFile:45) ~[1.8.7.jar:?]
	at gq.a(SourceFile:10) ~[1.8.7.jar:?]
	at fh$1.run(SourceFile:13) ~[1.8.7.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at g.a(SourceFile:60) ~[1.8.7.jar:?]
	... 3 more
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
	at bcy.a(SourceFile:600) ~[1.8.7.jar:?]
	at hu.a(SourceFile:41) ~[1.8.7.jar:?]
	at hu.a(SourceFile:8) ~[1.8.7.jar:?]
	at fh$1.run(SourceFile:13) ~[1.8.7.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at g.a(SourceFile:60) ~[1.8.7.jar:?]
	... 3 more
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
[14:41:33] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_25]
	at g.a(SourceFile:61) [1.8.7.jar:?]
	at ave.av(SourceFile:880) [1.8.7.jar:?]
	at ave.a(SourceFile:325) [1.8.7.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:124) [1.8.7.jar:?]
Caused by: java.lang.NullPointerException
	at bcy.a(SourceFile:964) ~[1.8.7.jar:?]
	at gq.a(SourceFile:45) ~[1.8.7.jar:?]
	at gq.a(SourceFile:10) ~[1.8.7.jar:?]
	at fh$1.run(SourceFile:13) ~[1.8.7.jar:?]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_25]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_25]
	at g.a(SourceFile:60) ~[1.8.7.jar:?]
	... 3 more
[14:41:33] [Client thread/FATAL]: Error executing task

This relates to:

MC-81649

MobileCrafter 2015-07-02T20:04:15Z

I reproduced the Error Messages by just playing on a Server.
The Server uses the 1.8 Spigot Protocol Hack.
Here the log: http://pastebin.com/3grZPM47

GoodKingFilms 2016-06-13T16:36:17Z

Still an issue in 1.10! Could a mod please update the affected versions to 1.10? Thank you

pokechu22 2016-07-23T03:45:18Z

Feels related to [MC-86947] or [MC-92079] (though that was fixed, I believe it's the same type of issue, joining multiple instances at once).

migrated 2016-11-06T11:10:05Z

Is this still an issue in the latest snapshot 16w44a? If so please update the affected versions.

This is an automated comment on any open or reopened issue with out-of-date affected versions.

migrated 2017-07-21T22:17:11Z

This bug happened to me while connecting to a vanilla 1.12 server after being disconnected from a restarting server.

RimaNari 2018-02-07T08:27:19Z

This appears to be similar to a bug Xisumavoid showcased on Youtube. He demonstrates how this can be exploited to change the actual player position in a singleplayer world:

In a singleplayer world you are at coordinates x, y, z.
Log into a server (or possibly also another singleplayer world?) where you are at coordinates x', y', z'.
Before loading has finished, quickly cancel joining the server and instead open the singleplayer world again.
The client renders the server you were trying to join before canceling, however the actual block positions are different.
Leaving and re-opening the singleplayer world removes render glitches - you see the singleplayer world again, but you remain at the coordinates of the server, effectively teleporting you from x, y, z to x', y', z' in the singleplayer world.

This bug can not only be exploited but can happen by chance easily. Additionally there may be further things that can be exploited about this.

pokechu22 2018-02-07T17:02:33Z

Yeah, this is the same bug, or else this is the same family of bugs. (It could also be one of the ones marked as related, even the ones marked as fixed, as the weird loading is a symptom of some other underlying problem of being on two servers/worlds/something like that).

RimaNari 2018-02-07T18:21:29Z

Wouldn't it be a good idea to update the description of the bug then? Currently it only explains the issue of the chat being shared across two servers. If this bug is to represent all symptoms that are caused by the same underlying bug of the connection not getting cancelled, a more general description would be appropriate.

Maybe a new description could contain both the current version explaining the issue with chat and my description of the teleporting. Then it would be clear that this is not only a single symptom (or even only a "minor" issue with the chat - the teleporting seems more important to me), but in fact an issue with a broad spectrum of symptoms.

migrated 2019-09-24T05:13:31Z

I managed to reproduce this on 1.14.4 (by accident, of course)

migrated 2020-09-08T16:54:12Z

I reproduce this on 1.16.1

Avoma 2020-11-25T15:28:08Z

Relates to REALMS-5078.

migrated 2020-12-15T12:27:14Z

Moved from MC-12989

I've reproduced this issue on Minecraft 1.16.4. The chat, bossbar and tab screen are from the previous server, while the world, gamemode and position are of the current server (possibly other stuff belongs to one server or the other, this is what I could find so far; previous server is the server I joined, but quickly cancelled and current server is the server I joined after the cancellation of the first server). A side effect of this glitch is that I'm in "noclip"-mode: I can go through the terrain as if it's not there, while still seeing the terrain and being in creative mode.

Reproduction steps:

Join one server via Direct Connection and quickly press the Cancel button
Join a different server from the server list and wait until you're in the server
The two servers are merged in the way as stated above

While doing this I had the client game log screen opened (enabled from within the launcher), so the game log printed there can be found in the latest.log I've attached to this issue. I've also taken multiple screenshots while in this mode which I've also attached, showing various effects caused by this.

[media]

The "noclip"-mode allowing me to go directly into the ground

[media]

The chat: the top lines are from the previous server, while everything below is from the current server

[media]

The tab screen from the previous server

[media]

The bossbar from the previous server

In all these images, the world that can be seen in the background is of the current world.

Edit: Some more information. I cannot interact with the world in any way: I cannot place or breaks blocks, spawn entities via spawn eggs, bonemeal grass blocks, use flint and steal, shoot arrows (the animation plays, but no arrow is shot), use a trident or interact with doors, beds, chests and shulker boxes; hitboxes for blocks are missing. The client does seem to know where blocks are, because when trying to use a spawn egg, it correctly shows the arm swing animation when looking at a block, while not showing this animation when right clicking the air. Chunks don't load as normal: I can move through the world, but after a certain amount of chunks, they stop loading completely. When going too far outwards (roughly half an unloaded chunk), all chunks that were visible disappear completely. The permissions from the previous server also carry over to this one, I am operator level 4 in the current server, yet I can't execute commands which require such an op level. The only commands I can use are commands from the previous server. Trying to execute those commands doesn't (visually) do anything. Chatting doesn't show my chat message. The social interactions screen also shows the players from the previous server, but shows the current server as the host name.

[media]

My armor of the previous server is also transferred over to this server. I've amended a screenshot to show this. (The effects are from the current server after eating an enchanted golden apple, this is as intended.)

[media]

After rejoining my armor items and items in my inventory (I put one piece of armor in my normal inventory, left two in my armor slots) stay in my inventory. This is potentially problematic, as then I can transfer armor from one server to another. (I could for example, get myself overpowered netherite armor from a creative server to a survival server.) This might warrant raising the priority of this issue or making this private.

[media]

migrated 2021-08-27T14:18:04Z

I managed to reproduce this on accident on 1.16.5, though I didn't cancel the joining, I just joined mineclub while opening my minecraft server on localhost and managed to join both servers at once, actionbars and chat were updated at real time from the other server and this kept on even after relogging from my minecraft server, and I couldn't join mineclub because it said I was already there.

[media]

It was constantly flickering between mine and their actionbar and mine and their time on the minecraft world, so it was going night and day constantly and I managed to join with their server texture;

So basically I'd get a very weird buggy relay from their minecraft server.

migrated 2021-12-03T03:41:19Z

[media]

^1.18
^{My game previously crashed and I tried to rejoin my friend's realm}
^{I was denied twice}
^{I went to Hypixel to see if it was my computer or the realm}
^{It dropped me in the realm with the gui and collision of Hypixel}
^{I left and tried to join the realm}
^{It worked but the Hypixel Chat was still there and flickering between day and night}
^{I got shot by a skeleton and was sent to the AFK Hub in Hypixel from the realm}
^{Got shot again and was sent to a Hypixel Lobby}
^{Started to fly away and finally died}
^{I couldn't respawn and left the server for it to finally fix itself}

^{the entire time I had my gear from the realm.}

plumparrot71568 2022-07-04T20:03:03Z

Can confirm in 1.17.1 (Hypixel + my private server)

[media]

plumparrot71568 2022-07-04T20:33:50Z

This appears to have been fixed in version 1.18, as I cannot reproduce the issue in any version that is 1.18 or newer.

migrated 2022-07-05T13:29:50Z

I encountered this years ago but didn't think nothing of it until I saw a video by "TheMisterEpic" released July 2 2022. Video here: https://www.youtube.com/watch?v=EEG_c3ycDg4 I still have my old screenshot so I'm adding it. I was on Thesevensaints and geovillage and was getting server info from both servers. Sevensaints was sending info in the chat and geovillage was sending in the tab screen although was showing players from sevensaints.