Development Assistance Plugin error

I have an error with my plugin. And I'm not so good with errors. Can someone help me?

Error (open) Error (close)

[14-12 21:29:34 ] [Server] ERROR Could not load 'plugins/Utilisals.jar' in folder 'plugins'
[14-12 21:29:34 ] [Server] [Informatie] org.bukkit.plugin.InvalidPluginException: java.lang.UnsupportedClassVersionError: me/didjee2/MainClass : Unsupported major.minor version 52.0
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:133) ~[spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:336) ~[spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:258) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.craftbukkit.v1_7_R4.CraftServer.loadPlugins(CraftServer.java:369) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.craftbukkit.v1_7_R4.CraftServer.reload(CraftServer.java:864) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.Bukkit.reload(Bukkit.java:301) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:181) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchCommand(CraftServer.java:767) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchServerCommand(CraftServer.java:753) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at net.minecraft.server.v1_7_R4.DedicatedServer.aB(DedicatedServer.java:326) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:290) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:584) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
[14-12 21:29:34 ] [Server] [Informatie] at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:490) [spigot1.8.old.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]

The MainClass:

Code:

package me.didjee2;

import java.util.HashMap;
import java.util.logging.Logger;

import me.didjee2.Commands.CommandBroadcast;
import me.didjee2.Commands.CommandClear;
import me.didjee2.Commands.CommandUtilisals;
import me.didjee2.Commands.CommandDay;
import me.didjee2.Commands.CommandEnderchest;
import me.didjee2.Commands.CommandFly;
import me.didjee2.Commands.CommandGamemode;
import me.didjee2.Commands.CommandHeal;
import me.didjee2.Commands.CommandHome;
import me.didjee2.Commands.CommandKick;
import me.didjee2.Commands.CommandNight;
import me.didjee2.Commands.CommandRain;
import me.didjee2.Commands.CommandSetHome;
import me.didjee2.Commands.CommandSpawn;
import me.didjee2.Commands.CommandSpeed;
import me.didjee2.Commands.CommandSuicide;
import me.didjee2.Commands.CommandSun;
import me.didjee2.Commands.CommandTop;
import me.didjee2.Commands.CommandTp;
import me.didjee2.Commands.CommandTphere;
import me.didjee2.Commands.CommandVanish;
import me.didjee2.Commands.CommandWarp;
import me.didjee2.Commands.CommandWorkbench;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Server;
import org.bukkit.command.PluginCommand;
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.configuration.file.FileConfigurationOptions;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.block.SignChangeEvent;
import org.bukkit.event.player.AsyncPlayerChatEvent;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;

public class MainClass
  extends JavaPlugin
  implements Listener
{
  public static Plugin instance;
  public HashMap<Player, Boolean> enabled = new HashMap<Player, Boolean>();
  public HashMap<Player, Integer> speed = new HashMap<Player, Integer>();
 
  public void onEnable()
  {
    Bukkit.getServer().getPluginManager().registerEvents(this, this);
   

    getConfig().options().copyDefaults(true);
    saveConfig();
   
    instance = this;
   
    getLogger().info("The plugin is enabled.");
    loadCommands();
  }
 
  @EventHandler
  public void Sign(SignChangeEvent event)
  {
    Player p = event.getPlayer();
    if (!p.hasPermission("Utilisals.SignColor")) {
      return;
    }
    for (int i = 0; i <= 3; i++)
    {
      String line = event.getLine(i);
     
      line = ChatColor.translateAlternateColorCodes('&', line);
      event.setLine(i, line);
    }
  }
 
  @EventHandler
  public void onChat(AsyncPlayerChatEvent e)
  {
    Player p = e.getPlayer();
    if (!p.hasPermission("Utilisals.ChatColor")) {
      return;
    }
    for (int i = 0; i <= 3; i++)
    {
      String chat = e.getMessage();
      chat = ChatColor.translateAlternateColorCodes('&', chat);
      e.setMessage(chat);
    }
  }
 
  public void loadCommands()
  {
        getCommand("Heal").setExecutor(new CommandHeal());
        getCommand("Fly").setExecutor(new CommandFly());
        getCommand("Gamemode").setExecutor(new CommandGamemode());
        getCommand("Utilisals").setExecutor(new CommandUtilisals());
        getCommand("Clear").setExecutor(new CommandClear());
        getCommand("SetSpawn").setExecutor(new CommandSpawn());
        getCommand("Spawn").setExecutor(new CommandSpawn());
        getCommand("Day").setExecutor(new CommandDay());
        getCommand("Night").setExecutor(new CommandNight());
        getCommand("Sun").setExecutor(new CommandSun());
        getCommand("Rain").setExecutor(new CommandRain());
       


        getCommand("Teleport").setExecutor(new CommandTp());
        getCommand("Tphere").setExecutor(new CommandTphere());
        getCommand("Broadcast").setExecutor(new CommandBroadcast());
        getCommand("Warp").setExecutor(new CommandWarp());
        getCommand("SetWarp").setExecutor(new CommandWarp());
        getCommand("Speed").setExecutor(new CommandSpeed());
        getCommand("Suicide").setExecutor(new CommandSuicide());
        getCommand("Money").setExecutor(new Money());
        getCommand("home").setExecutor(new CommandHome());
        getCommand("sethome").setExecutor(new CommandSetHome());
        getCommand("Enderchest").setExecutor(new CommandEnderchest());
        getCommand("workbench").setExecutor(new CommandWorkbench());
        getCommand("Vanish").setExecutor(new CommandVanish());
        getCommand("kick").setExecutor(new CommandKick());
        getCommand("top").setExecutor(new CommandTop());
  }
 
  public static Plugin getInstance()
  {
    return instance;
  }
}

I hope that you guys can help me!

 

Oh, that's simple enough. First line says it all. Update your Java to 1.8 or recompile your program in 1.6, because you are compiling your program in a newer version of Java than you have installed in your runtime.