Помогите Почему не работает плагин?

Хотел сделать плагин который выдает сообщение при входе на сервер! Но почему-то он не работает...
Вот скрины --->

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Код Welcome.java:

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package ru.rumaingames.welcomer;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Sound;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class Welcome extends JavaPlugin implements Listener {

private static Welcome instance;

public static Welcome instance() {
return instance;
}

public void onEnable() {
Bukkit.getServer().getPluginManager().registerEvents(this, this);
}

public void onDisable() {

}

@EventHandler
public void onPlayerJoin (PlayerJoinEvent e) {
Player p = e.getPlayer();

p.sendMessage(ChatColor.GREEN + "Hello!");
p.playSound(p.getLocation(), Sound.NOTE_PIANO, 1, 1);
}
}

Код plugin.yml:

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name: Welcome
main: ru.rumaingames.welcomer.Welcome
description: Plugin create Ru-MainGames for server Ultimate
version: 1.0

Сам jar файл:

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https://yadi.sk/d/xYr8bWfaftWMt

Логи сервера после запуска плагина:

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[23:19:20] [Server thread/INFO]: Starting minecraft server version 1.7.2
[23:19:20] [Server thread/INFO]: Loading properties
[23:19:20] [Server thread/INFO]: Default game type: SURVIVAL
[23:19:20] [Server thread/INFO]: Generating keypair
[23:19:20] [Server thread/INFO]: Starting Minecraft server on *:25565
[23:19:21] [Server thread/INFO]: This server is running CraftBukkit version git-Bukkit-1.7.2-R0.3-b3020jnks (MC: 1.7.2) (Implementing API version 1.7.2-R0.3)
[23:19:21] [Server thread/ERROR]: Could not load 'plugins\Welcome.jar' in folder 'plugins'
org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: ru/rumaingames/welcomer/Welcome : Unsupported major.minor version 52.0
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:137) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:313) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:236) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugins(CraftServer.java:350) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.craftbukkit.v1_7_R1.CraftServer.<init>(CraftServer.java:312) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at net.minecraft.server.v1_7_R1.PlayerList.<init>(PlayerList.java:63) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at net.minecraft.server.v1_7_R1.DedicatedPlayerList.<init>(SourceFile:14) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at net.minecraft.server.v1_7_R1.DedicatedServer.init(DedicatedServer.java:126) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:424) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
Caused by: java.lang.UnsupportedClassVersionError: ru/rumaingames/welcomer/Welcome : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method) ~[?:1.7.0_45]
at java.lang.ClassLoader.defineClass(Unknown Source) ~[?:1.7.0_45]
at java.security.SecureClassLoader.defineClass(Unknown Source) ~[?:1.7.0_45]
at java.net.URLClassLoader.defineClass(Unknown Source) ~[?:1.7.0_45]
at java.net.URLClassLoader.access$100(Unknown Source) ~[?:1.7.0_45]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_45]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.7.0_45]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_45]
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.7.0_45]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:77) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:62) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_45]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.7.0_45]
at java.lang.Class.forName0(Native Method) ~[?:1.7.0_45]
at java.lang.Class.forName(Unknown Source) ~[?:1.7.0_45]
at org.bukkit.plugin.java.PluginClassLoader.<init>(PluginClassLoader.java:40) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[craftbukkit-1.7.2-R0.3.jar:git-Bukkit-1.7.2-R0.3-b3020jnks]
... 9 more
[23:19:21] [Server thread/WARN]: **** SERVER IS RUNNING IN OFFLINE/INSECURE MODE!
[23:19:21] [Server thread/WARN]: The server will make no attempt to authenticate usernames. Beware.
[23:19:21] [Server thread/WARN]: While this makes the game possible to play without internet access, it also opens up the ability for hackers to connect with any username they choose.
[23:19:21] [Server thread/WARN]: To change this, set "online-mode" to "true" in the server.properties file.
[23:19:21] [Server thread/INFO]: Preparing level "world"
[23:19:21] [Server thread/INFO]: Preparing start region for level 0 (Seed: 8947996205200849129)
[23:19:22] [Thread-7/WARN]: Could not get information about this CraftBukkit version; perhaps you are running a custom one?: FileNotFoundException
[23:19:22] [Server thread/INFO]: Preparing spawn area: 36%
[23:19:23] [Server thread/INFO]: Preparing start region for level 1 (Seed: 8947996205200849129)
[23:19:23] [Thread-7/WARN]: Could not get latest artifact information: FileNotFoundException
[23:19:24] [Server thread/INFO]: Preparing spawn area: 60%
[23:19:24] [Server thread/INFO]: Preparing start region for level 2 (Seed: 8947996205200849129)
[23:19:25] [Server thread/INFO]: Server permissions file permissions.yml is empty, ignoring it
[23:19:25] [Server thread/INFO]: Done (3,906s)! For help, type "help" or "?"

 

Что именно не работает?

 

плагин, не отображается даже

 

Кинь jar, который у тебя получается

 

https://yadi.sk/d/xYr8bWfaftWMt

 

При компиляции используй 7-ю java

 

А как изменить java? только при создании проекта?[DOUBLEPOST=1428625526,1428625113][/DOUBLEPOST]

Нашел как изменить java, помогло спасибо помог очень!!!