[MC-108343] Minecraft crashes with "java.lang.NullPointerException: Ticking screen" while pinging server on multiplayer server list (previously due to network issues, now more frequent)

Note

This issue is about the game crash (back to the launcher) when opening the server list. For the similar-sounding, but completely different, disconnect with a NullPointerException while in-game, see MC-115942.

What I expected to happen was...:
Minecraft to be staying idle on the background minimalized without any issuse
What actually happened was...:
It crashed with a Ticking screen error
Steps to Reproduce:
1. Open minecraft 1.10.2
2. Minimilize it
3. maybe open a second minecraft and see if thas the issuse

Description: Ticking screen

java.lang.NullPointerException: Ticking screen
	at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:273)
	at io.netty.bootstrap.Bootstrap.doConnect(Bootstrap.java:150)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:132)
	at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:113)
	at bls.b(SourceFile:165)
	at bls.a(SourceFile:45)
	at bls$1.a(SourceFile:144)
	at eo.l(SourceFile:382)
	at bls.a(SourceFile:254)
	at bhj.e(SourceFile:116)
	at bcx.t(SourceFile:1601)
	at bcx.av(SourceFile:968)
	at bcx.a(SourceFile:396)
	at net.minecraft.client.main.Main.main(SourceFile:124)

Hopper tickets

MCX-2842585 (1.10.2)
MCX-3487283 (17w14a)

Code analysis

Based on 1.11 decompiled using MCP 9.35 rc1

It looks like this crash can happen when the method net.minecraft.client.network.ServerPinger.ping(ServerData) was called while the user had an internet connection, but before a packet was received the internet connection was lost. Additionally the server needs to have a hostname which is not a literal IP address. In that case at some point the method net.minecraft.client.network.ServerPinger.ping(...).new INetHandlerStatusClient() {...}.onDisconnect(ITextComponent) is called. The problem lies in the method io.netty.bootstrap.Bootstrap.checkAddress(SocketAddress) which does check if the provided SocketAddress is an instance of InetSocketAddress (which include a null) check, but does not test if the method getAddress() returns null. This is the case if the host name cannot be resolved. As this netty version seems to be a custom build it should be fixable by Mojang.

Linked issues

is duplicated by 25

MC-110245 Minecraft 1.11 crashes when Refresh is clicked several times on Multiplayer screen. Resolved

MC-111588 crash of server Resolved

MC-112386 Crash: Ticking screen 'java.lang.NullPointerException: Ticking screen' Resolved

MC-113299 it was lagging and it crash Resolved

MC-113302 Crash Report Resolved

20 more links

Attachments

crash-2016-10-06_16.06.35-client.txt

crash-2017-04-07_13.32.58-client.txt

crash-2017-04-28_16.41.39-client.txt

Comments 18

kumasasa 2016-10-06T19:33:11Z

OpenGL: Intel(R) Iris(TM) Pro Graphics 580 GL version 4.4.0 - Build 20.19.15.4474, Intel

This is an inofficial Intel graphics driver. Latest version is 15.xx.xx.xx, not 20.xx.xx.xx

Please obtain the latest driver from http://downloadcenter.intel.com and report if the error is persisting.

Tron 2017-04-12T16:48:24Z

Seems to be more common now in 17w15a and 17w14a, possibly breaks on more than just connection issues now?

EarlyReflections 2017-04-13T00:37:16Z

I'm wondering what this has to do with a supposedly problematic internet connection. My connection cannot be at fault all day and every day when it works perfectly fine for everything else.

The crash occurs over 95% of the times when I minimize the game window. It also happens when I play single player, without ever going to the multiplayer list. There's no server pinging happening and it still crashes at ticking screen, over 90% of the times when the game window is minimized.

That never happened to me before 17w14a and it seems worse in 17w15a.

pokechu22 2017-04-13T00:45:46Z

It might have had to deal with a problematic internet connection before, but recently something definitely changed. Most likely, that something is updating netty (which happened in that snapshot). (I'll add: minimized doesn't seem like a factor for the multiplayer UI in 17w14a).

I'm currently looking at what might have changed in netty between versions - might be a bug on their end.

It also happens when I play single player, without ever going to the multiplayer list. There's no server pinging happening and it still crashes at ticking screen, over 90% of the times when the game window is minimized.

That's weird. It might be that there's two different issues, one from netty and one from minimizing. Note that "ticking screen" is a very wide category of crashes (it means that something went wrong when it was handling a GUI). Just the top most line of the stacktrace from a single-player crash should be enough to see if somehow it's still from netty - if it isn't, then a new issue should be created.

EarlyReflections 2017-04-13T03:04:33Z

OK, I was dead wrong about it occurring in single player without netty being involved. After spending over an hour in troubleshooting mode and being unsuccessful in reproducing the issue, I decided to go to the multiplayer server list.

It only took a few seconds from there. I minimized the window to go back to browsing and there goes the crash and netty is right there in the first lines:

at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:358)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:162)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:143)

I checked all previous crash reports since this issue started (april 5th), and these 4 lines of the stack trace are always identical.

I guess it did happen after closing my single player world because I probably went to the multiplayer server list screen some time before.

Are the "network issues" mentioned here refer to server-side or client-side network issues? Like, if some server is too slow or fails to return a ping?

8 more comments

Timbawolf27 2017-04-13T23:11:12Z

I get the same message and kept getting kicked from my server but it seemed like it only happened when I approached a parrot, then I would get kicked and rejoin and kicked like 2 seconds later saying: Internal Exception io.netty.handler.codec.decoderexception java.lang.nullpointerexception. After the parrot would be killed I had no issues but then for the heck of it I went on creative and spawned a parrot and was immediately disconnected. I am playing on a 1.7.2 generated world but have never had this issue.

marcono1234 2017-04-14T10:00:07Z

Are the "network issues" mentioned here refer to server-side or client-side network issues? Like, if some server is too slow or fails to return a ping?

@@unknown at least the case described in the code analysis of the report is caused by client-side network issues, but it could be more visible if the server takes long to send packets back since the time span is longer then which makes it more likely that you have network issues during that.

@@unknown what do you mean by "I get the same message"? As @unknown said before "ticking screen" is only a crash report category. Additionally the error message and situation you are describing sounds pretty unrelated to this report. It is probably rather MC-115942.

EarlyReflections 2017-04-14T13:06:11Z

@Marcono1234

Understood. However, I don't think I have network issues or I would have symptoms of it showing in other instances on my system. The fact that only Minecraft crashes tells me it's the sole culprit by not handling the situation gracefully. Throwing errors in the logs would be far better than crashing, in my opinion.

Momibelle 2017-04-14T14:35:52Z

We have run into the same client-side issue here. I had an entire classroom of kids being kicked from our snapshot with the error message: Internal Exception: io.netty.handler.codec.DecoderException:java.lang.NullPointerException

At first it began with simply breaking blocks. Later I spawned in some parrots, and then all of the kids were kicked for either looking at a wild parrot, or trying to tame them. The tamed ones were fine.

I attempted to solve the problem by: replacing the jar file with a fresh one; removing all of the parrots; deleting all data files for individual players; rebooting the server multiple times. Nothing appears to be working.

We are playing on a new world generated in 17w14a.

marcono1234 2017-04-14T15:09:31Z

@@unknown as stated before in the answer to @@unknown's comment the issue you are describing is a different one: MC-115942. Please make sure that the error messages and the behavior are the same when searching for reports. In this case both differ, this report is about a crash while the other one is about being kicked from a server.

md_5 2017-04-15T07:45:45Z

I'm seeing this heaps in 17w15a, just leaving my client on in the background and it crashes:
java.lang.NullPointerException: Ticking screen
at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:358)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:162)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:143)
at bqz.b(SourceFile:241)
at bqz.a(SourceFile:45)
at bqz$1.a(SourceFile:144)
at gd.l(SourceFile:379)
at bqz.a(SourceFile:254)
at bls.e(SourceFile:115)
at bgu.t(SourceFile:1591)
at bgu.aw(SourceFile:959)
at bgu.a(SourceFile:399)
at net.minecraft.client.main.Main.main(SourceFile:123)

I'm also getting randomly disconnected from the server but there is no crash so I'm unsure if this is a contributor.

EarlyReflections 2017-04-20T15:21:25Z

Confirmed for 17w16a.

EarlyReflections 2017-04-21T19:11:06Z

Also in 17w16b.

md_5 2017-04-22T08:55:20Z

Confirming again also.
Worth noting that Netty was updated, so I think the catalyst for this happening so much now in the snapshots.

EarlyReflections 2017-04-27T16:12:17Z

Confirming 17w17b.

@Mitschi'
You can still play the snapshots. It doesn't crash right away and all the times, unless your client is having some other issues.

0xAA55 2017-05-09T04:31:00Z

Mine is:
Reported exception thrown!
f: Ticking screen
at bhm.t(SourceFile:1606)
at bhm.ax(SourceFile:964)
at bhm.a(SourceFile:404)
at net.minecraft.client.main.Main.main(SourceFile:123)
Caused by: java.lang.NullPointerException
at io.netty.bootstrap.Bootstrap.checkAddress(Bootstrap.java:358)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:162)
at io.netty.bootstrap.Bootstrap.connect(Bootstrap.java:143)
at brt.b(SourceFile:241)
at brt.a(SourceFile:45)
at brt$1.a(SourceFile:144)
at go.l(SourceFile:382)
at brt.a(SourceFile:254)
at bmq.e(SourceFile:115)
at bhm.t(SourceFile:1596)
... 3 more

- 2017-05-10T13:41:50Z

Confirming on 1.12-pre1
Crashes every time I go to 'multiplayer'
You basically can't play multiplayer anymore on macOS Sierra

enemysfriend22 2017-05-13T19:59:59Z

confirmed in 1.12pre2

https://www.youtube.com/watch?v=wvNDfexjsac

https://pastebin.com/ytScud6z

https://gyazo.com/deed0a254ce6fd0ff761ee08b70c370f