Launcher Update for Java 8 support?

[Sir-Will]

hey @sk89q,

when will you update the launcher for Java 8 support?
I get so many reports from players that they can't launch the modpacks because of this error:

java.util.ConcurrentModificationException
        at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
        at java.util.ArrayList$Itr.remove(Unknown Source)
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:114)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:27)
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256M; support was removed in 8.0
Java HotSpot(TM) 64-Bit Server VM warning: UseCMSCompactAtFullCollection is deprecated and will likely be removed in a future release.
Process ended with code: 0

[sk89q]

It works fine on Java 8. Those warnings don't mean anything.

As for the ConcurrentModificationException, that looks like a different error.

[Sir-Will]

Hm, I allways tell them to downgrade to java 7 and then it works for them. You think it is a issue with a mod?

[sk89q]

I'm not sure. ConcurrentModificationException is a very unhelpful error usually.

It usually happens either because two threads are accessing the same object at once (when the object is not thread-safe) or some code iterating through a list modifies the list before it has finished iterating and screws itself over.

I'd have to see what Launch.launch() does.

You could of course try running with no mods.

[Sir-Will]

As I had java 8 (Update 5) installed I tried to start a modpack with it and it worked. Now I installed java 8 update 20 and I get the same error. I also disabled all mods and it still doesn't work. I did the same test on multi mc and I get the same issue with Forge 965 but not with vanilla.

[sk89q]

OK I got a chance to look into the error.

It's an issue with FML. I could fork launchwrapper to work around it.

It's an issue on Java 8 presumably because Java got a little more stringent about catching things that programmers should not be doing.

Links for myself:

https://github.com/Mojang/LegacyLauncher/blob/master/src/main/java/net/minecraft/launchwrapper/Launch.java#L118

https://github.com/MinecraftForge/FML/blob/master/src/main/java/cpw/mods/fml/common/launcher/FMLInjectionAndSortingTweaker.java#L35

[sk89q]

It should be "fixed" in this branch:
https://github.com/SKCraft/MojangLegacyLauncher/compare/tweaker-cme-workaround

It also means updating to launchwrapper 1.11 from 1.9.

Try: https://github.com/SKCraft/MojangLegacyLauncher/releases/tag/tweaker-cme-workaround-r1 (get the .jar download)

Easy test: In your launcher's (not modpack) libraries folder, make a backup of the old net/minecraft/launchwrapper-1.9.jar and replace the file with my version.

---

Using it in your modpack:

Note: It seems to work but I have barely tested it. I also have not tested the following instructions.

You will have change:

        {
            "name": "net.minecraft:launchwrapper:1.9",
            "serverreq": true
        }

to

        {
            "name": "com.skcraft.mojang:launchwrapper:1.11-r1",
            "serverreq": true
        }

in version.json

and upload launchwrapper-1.11.jar to $libraries_url/com/skcraft/mojang/1.11-r1/launchwrapper-1.11-r1.jar

[Slind14]

mhh, does this one only work with 1.7? It does require log4j and after I added it I still got NoSuchMethod errors

[sk89q]

"this"?

[Slind14]

@sk89q com/skcraft/mojang/1.11-r1/launchwrapper-1.11-r1.jar

I still have a few 1.6 modpacks, which is why I am asking. I couldn't get it to work with those.

[sk89q]

Closing due to age.