Because I intend to upgrade my server to 1.12 in future, I ran some tests and found out that PaperSpigot #1113 [https://ci.destroystokyo.com/job/PaperSpigot/1113/] and beyond crashes MobHunting. All prior 1.12 releases (#1105 - #1112) have no problem at all.

MobHunting wasn't alone on this. MyWarp and MyPet would also work fine before but start crashing from #1113. I'm not sure whether I should report this to all respective plugin programmers or to the PaperSpigot team?

Anyhow, here's the error.

[11:33:07 INFO]: [MobHunting] Enabling MobHunting v4.9.5-SNAPSHOT-B407
[11:33:07 ERROR]: Error occurred while enabling MobHunting v4.9.5-SNAPSHOT-B407 (Is it up to date?)
java.lang.NoClassDefFoundError: org/bukkit/craftbukkit/libs/jline/internal/InputStreamReader
at one.lindegaard.MobHunting.MobHunting.onEnable(MobHunting.java:123) ~[?:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264) ~[patched_1.12.jar:git-Paper-1123]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:316) [patched_1.12.jar:git-Paper-1123]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:404) [patched_1.12.jar:git-Paper-1123]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugin(CraftServer.java:378) [patched_1.12.jar:git-Paper-1123]
at org.bukkit.craftbukkit.v1_12_R1.CraftServer.enablePlugins(CraftServer.java:328) [patched_1.12.jar:git-Paper-1123]
at net.minecraft.server.v1_12_R1.MinecraftServer.t(MinecraftServer.java:441) [patched_1.12.jar:git-Paper-1123]
at net.minecraft.server.v1_12_R1.MinecraftServer.l(MinecraftServer.java:402) [patched_1.12.jar:git-Paper-1123]
at net.minecraft.server.v1_12_R1.MinecraftServer.a(MinecraftServer.java:340) [patched_1.12.jar:git-Paper-1123]
at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:290) [patched_1.12.jar:git-Paper-1123]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:615) [patched_1.12.jar:git-Paper-1123]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_131]
Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:92) ~[patched_1.12.jar:git-Paper-1123]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:87) ~[patched_1.12.jar:git-Paper-1123]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_131]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_131]
... 12 more

Released V4.9.5

First of all, you should chance to newest snapshot. Build 407 has lag problems when you kill a mob.

And about the bug, Im not sure if Paper can do anything about this and why it suddenly comes after we have moved to MC1.12, its probaly because Mojang have made alot of essential changes in their code, and they have removed a lot old code. On the other hand Spigot MC does not have this problem, so it might help that you posted a ticket at the PaperClip team.

Im not sure how I remove this bug, but I have seen an update for some of these plugins I use, so I will contact the dev and ask what he did.

PS.

When you get these bugs, you should always focus on the last part "Caused by:"

Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:92) ~[patched_1.12.jar:git-Paper-1123]

It tells you where in the code it actually failed. In this case "PluginClassLoader.java:92" in the JAR "patched_1.12.jar"

If it were mobhunting It would have a reference to Mobhunting-V4.9.5-SNAPHOT-407.jar

Ste3et/FurnitureLib#27 (comment)

I'm not using the developer's build on my real server. Everything works pretty fine at 4.9.4 but will update to 4.9.5 when you release it.

To clarify once more, PaperSpigot has released 1.12 server versions that DO work without errors. #1105 - #1112 (8 releases) didn't have those problems. #1113 - #1123 however, do. So whatever they added in #1113 ("Improve console implementation") is what's causing the error. Well, I guess it wouldn't hurt to post a ticket.

Could've sworn I used B414 on my test server, but B414 says pretty much the same thing.

Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:92) ~[patched_1.12.jar:git-Paper-1113]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:87) ~[patched_1.12.jar:git-Paper-1113]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_131]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_131]
... 12 more

Edit: "Paper recently replaced CraftBukkit's logging system with a better one and now your plugin no longer runs on Paper because of this change." Maybe this is what happened to #1113? They sure didn't mention it.

I think I have fixed this problem in Build 413.
https://fractal.lindegaard.one:8181/job/MobHunting/

I replaced org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader
with java.io.InputStreamreader

Im still at work, so Im not able to start my PaperClip server and as far as I remember I have not made a Paper 1.12 test server yet. If you can help testing it would be nice.

Build 414 is compiled 2 min ago. So Im sure you have not tested that :-)

414 fixed the problem! No error messages!

This ticket helped me solving the problem. (If any other developer have the same problem)
Ste3et/FurnitureLib#27 (comment)

Thanks, I will release v.4.9.5 tonight, when Im back from work :-)

And once again. THANKS for your great help with the testing. It is very useful!

Glad to help. Well, it benefits me as well =)

414 seems to work fine on 1.11.2 as well.