Config.yml for this?

Hey bukkit dev programmers,
I am having troubles making this configurable, it seems to turn back to 1, whenever I save and reload the file and server.

Main

Code:java

    public void onEnable() {
        getLogger().info("Has Been Enabled!");
        getLogger().warning("You are using an older version of this plugin!");
        PluginManager pm = getServer().getPluginManager();
        pm.registerEvents(new Method(), this);
        pm.registerEvents(new Method2(), this);
        pm.registerEvents(new Method2Return(), this);
        pm.registerEvents(new StopPlace(), this);
        hrecipe();
        getConfig().options().copyDefaults(true);
        if(!getConfig().contains("Damage")){ //Checks if the config does not have "Damage" in it.
        getConfig().set("Damage", 0.75);
        }
        saveConfig();
        }

Damage Listener Class

Code:java

package me.ProMCKingz.VIP;
 
import org.bukkit.Material;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDamageByEntityEvent;
 
public class Damage implements Listener {
 
    Main configGetter;
    public Damage(Main plugin){
        plugin.getServer().getPluginManager().registerEvents(this, plugin);
        configGetter = plugin;
    }
    double Damage = configGetter.getConfig().getDouble("Damage");   
    @EventHandler
    public void onDamage(EntityDamageByEntityEvent e) {
        // First you should check if e.getEntity() is not a Player and just
        // return;
        // since it doesn't matter to you
        if (!(e.getEntity() instanceof Player))
            return;
        // Then as you are sure you have a Player being attacked, you can cast
        // entity to Player
        Player entity = (Player) e.getEntity();
        // check if he has a Piston in his hand
        if (entity.getItemInHand().getType() == Material.PISTON_STICKY_BASE) {
            e.setDamage(e.getDamage()*Damage);
 
        }
    }
 
}
 

 

Hey idk whats wrong but can you help me with this I have a plugin Draw My Thin and it has a screen on witch you can draw but if you draw at any other place besides the screen of wool it displays this http://prntscr.com/47hjgg
Please help