using the linux version of minecraft, just freshly installed and i go to demo. looks like same issue running my java version.
[01:02:43 INFO]: Minecraft Launcher 1.6.89-j (through bootstrap 5) started on linux...[01:02:43 INFO]: Minecraft Launcher 1.6.89-j (through bootstrap 5) started on linux...[01:02:43 INFO]: Current time is Dec 25, 2019, 1:02:43 AM[01:02:43 INFO]: System.getProperty('os.name') == 'Linux'[01:02:43 INFO]: System.getProperty('os.version') == '4.16.18-galliumos'[01:02:43 INFO]: System.getProperty('os.arch') == 'amd64'[01:02:43 INFO]: System.getProperty('java.version') == '11.0.5'[01:02:43 INFO]: System.getProperty('java.vendor') == 'Private Build'[01:02:43 INFO]: System.getProperty('sun.arch.data.model') == '64'[01:02:43 INFO]: proxy == DIRECT[01:02:44 INFO]: Refreshing local version list...[01:02:44 INFO]: Refreshing remote version list...[01:02:45 INFO]: Refresh complete.[01:02:46 INFO]: Loaded 2 profile(s); selected '(Default)'[01:02:46 INFO]: Refreshing auth...[01:02:46 INFO]: Logging in with access token[01:02:49 INFO]: Getting syncinfo for selected version[01:02:49 INFO]: Queueing library & version downloads[01:02:49 FATAL]: Unhandled exception in thread Thread[pool-2-thread-2,5,main]com.google.gson.JsonSyntaxException: duplicate key: null at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:191) ~[Minecraft.jar:?] at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:146) ~[Minecraft.jar:?] at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:93) ~[Minecraft.jar:?] at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:172) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:795) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:761) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:710) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:682) ~[Minecraft.jar:?] at net.minecraft.launcher.updater.RemoteVersionList.getCompleteVersion(RemoteVersionList.java:32) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:213) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:37) ~[launcher.jar:1.6.89-j] at com.mojang.launcher.game.runner.AbstractGameRunner.playGame(AbstractGameRunner.java:67) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.game.GameLaunchDispatcher$1.run(GameLaunchDispatcher.java:111) ~[launcher.jar:1.6.89-j] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[?:?] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[?:?] at java.base/java.lang.Thread.run(Thread.java:834) [?:?]
zortan
using the linux version of minecraft, just freshly installed and i go to demo. looks like same issue running my java version.
[01:02:43 INFO]: Minecraft Launcher 1.6.89-j (through bootstrap 5) started on linux...[01:02:43 INFO]: Minecraft Launcher 1.6.89-j (through bootstrap 5) started on linux...[01:02:43 INFO]: Current time is Dec 25, 2019, 1:02:43 AM[01:02:43 INFO]: System.getProperty('os.name') == 'Linux'[01:02:43 INFO]: System.getProperty('os.version') == '4.16.18-galliumos'[01:02:43 INFO]: System.getProperty('os.arch') == 'amd64'[01:02:43 INFO]: System.getProperty('java.version') == '11.0.5'[01:02:43 INFO]: System.getProperty('java.vendor') == 'Private Build'[01:02:43 INFO]: System.getProperty('sun.arch.data.model') == '64'[01:02:43 INFO]: proxy == DIRECT[01:02:44 INFO]: Refreshing local version list...[01:02:44 INFO]: Refreshing remote version list...[01:02:45 INFO]: Refresh complete.[01:02:46 INFO]: Loaded 2 profile(s); selected '(Default)'[01:02:46 INFO]: Refreshing auth...[01:02:46 INFO]: Logging in with access token[01:02:49 INFO]: Getting syncinfo for selected version[01:02:49 INFO]: Queueing library & version downloads[01:02:49 FATAL]: Unhandled exception in thread Thread[pool-2-thread-2,5,main]com.google.gson.JsonSyntaxException: duplicate key: null at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:191) ~[Minecraft.jar:?] at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:146) ~[Minecraft.jar:?] at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:93) ~[Minecraft.jar:?] at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:172) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:795) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:761) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:710) ~[Minecraft.jar:?] at com.google.gson.Gson.fromJson(Gson.java:682) ~[Minecraft.jar:?] at net.minecraft.launcher.updater.RemoteVersionList.getCompleteVersion(RemoteVersionList.java:32) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:213) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:37) ~[launcher.jar:1.6.89-j] at com.mojang.launcher.game.runner.AbstractGameRunner.playGame(AbstractGameRunner.java:67) ~[launcher.jar:1.6.89-j] at net.minecraft.launcher.game.GameLaunchDispatcher$1.run(GameLaunchDispatcher.java:111) ~[launcher.jar:1.6.89-j] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[?:?] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[?:?] at java.base/java.lang.Thread.run(Thread.java:834) [?:?]