[SEVERE] Could not load 'plugins\mcore.jar' in folder 'plugins' (running Java 7) about massivecore HOT 4 CLOSED

However, I'm having the same issue, latest craftbukkit and mcore, with java 7

java version 7

$ update-java-alternatives -l
java-1.7.0-openjdk-amd64 1071 /usr/lib/jvm/java-1.7.0-openjdk-amd64
$ java -version
java version "1.7.0_25"
OpenJDK Runtime Environment (IcedTea 2.3.10) (7u25-2.3.10-1ubuntu0.12.10.2)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

and my log output

02:13:37 [INFO] This server is running CraftBukkit version git-Bukkit-1.6.2-R1.0-b2879jnks (MC: 1.6.2) (Implementing API version 1.6.2-R1.0)
02:13:37 [SEVERE] Could not load 'plugins/mcore.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: net/minecraft/server/v1_6_R3/PlayerInventory
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:184)
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
at org.bukkit.craftbukkit.v1_6_R2.CraftServer.loadPlugins(CraftServer.java:239)
at org.bukkit.craftbukkit.v1_6_R2.CraftServer.(CraftServer.java:217)
at net.minecraft.server.v1_6_R2.PlayerList.(PlayerList.java:56)
at net.minecraft.server.v1_6_R2.DedicatedPlayerList.(SourceFile:11)
at net.minecraft.server.v1_6_R2.DedicatedServer.init(DedicatedServer.java:106)
at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:391)
at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_6_R3/PlayerInventory
at com.massivecraft.mcore.MCore.getMCoreGsonBuilder(MCore.java:81)
at com.massivecraft.mcore.MCore.(MCore.java:66)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:173)
... 9 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_6_R3.PlayerInventory
at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 14 more

from massivecore.

yes you do. you're a consumer, if they dont do what you want you take your business elsewhere, so tell them to put java 7 on it

(for reference i removed my last post after fixing my issue)

from massivecore.

The server is currently running Java 7.

from massivecore.

This is not Java 7 related. You are using incompatible versions of craftbukkit and mcore.

from massivecore.