Solved InvalidPluginException error after adding NMS code to plugin

The title pretty much says it tall. I threw this new code in my plugin to do a little testing on the NMS code for 1.8 titles.

Error from logs:

Code:

Could not load 'plugins\OreRunner.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/v1_8_R1/Packet
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:329) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:251) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugins(CraftServer.java:291) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.reload(CraftServer.java:740) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.Bukkit.reload(Bukkit.java:534) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:25) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:642) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.PlayerConnection.handleCommand(PlayerConnection.java:1135) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.PlayerConnection.a(PlayerConnection.java:970) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.PlayerConnectionUtils$1.run(SourceFile:13) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_66]
    at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_66]
    at net.minecraft.server.v1_8_R3.SystemUtils.a(SystemUtils.java:19) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:718) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:367) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:657) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:560) [spigot.jar:git-Spigot-f928e7a-f27339c]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_66]
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_8_R1/Packet
    at java.lang.Class.forName0(Native Method) ~[?:1.8.0_66]
    at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_66]
    at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    ... 21 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_8_R1.Packet
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:91) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:86) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_66]
    at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_66]
    at java.lang.Class.forName0(Native Method) ~[?:1.8.0_66]
    at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_66]
    at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:64) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:131) ~[spigot.jar:git-Spigot-f928e7a-f27339c]
    ... 21 more

Did I put down something wrong?

Code:

String text = player.getName();
           
IChatBaseComponent chatTitle = ChatSerializer.a("{\"text\": \"" + text + "\",color:" + ChatColor.GOLD.name().toLowerCase() + "}");
           
PacketPlayOutTitle title = new PacketPlayOutTitle(EnumTitleAction.TITLE, chatTitle);
PacketPlayOutTitle length = new PacketPlayOutTitle(5, 20, 5);
           
((CraftPlayer) player).getHandle().playerConnection.sendPacket(title);
((CraftPlayer) player).getHandle().playerConnection.sendPacket(length);

Would appreciate some help, thanks!

 

I bet your imports are from a jar that is not the same version as the one on your server...
It has to be the same version in both to work. Otherwise you can use Reflection to bypass this issue (comes with Some risks) or use other techniques

 

These imports do not exist. Are you sure your jar file is the same as the jar file you're building your plugin with?

 

Yes! Got it. Yep, you were correct @Zombie_Striker. I was using a different jar to build with then the jar that my server is running off of. Thanks for the help guys! Never would've thought it would be that. I thought I just coded something wrong.

 

@UNC00KED Another thing: If you want to support multiple versions, I'd recommend using abstraction to implement NMS. https://bukkit.org/threads/support-multiple-minecraft-versions-with-abstraction-maven.115810/