Solved Variables not saving when method is called

Hello I am new to doing Minecraft plugins and somewhat new to Java. I am trying to make my variables i call in the SynthWeapont1 method carry over to my GUI. The values stay at what I call them as originally before i call the method instead of changing (0, 0, and a blank string) I hope that makes sense.

Code (Text):

public void synthDamageT1(double dmax, double dmin, String rarity) {
     
        int raritydecide;
        raritydecide = (int)(Math.random() * 100) + 1;
     
        if (raritydecide < 70 && raritydecide >= 1) {
            dmax = 5;
            dmin = 1;
            rarity = "Common";
        } else if (raritydecide < 93 && raritydecide >= 70) {
            dmax = 7;
            dmin = 2;
            rarity = "Rare";
        } else if (raritydecide < 96 && raritydecide >= 93) {
            dmax = 13;
            dmin = 7;
            rarity = "Legendary";
        } else if (raritydecide < 98 && raritydecide >= 96) {
            dmax = 18;
            dmin = 10;
            rarity = "Exotic";
        } else if (raritydecide < 100 && raritydecide >= 98) {
            dmax = 30;
            dmin = 20;
            rarity = "Hyper";
        }
     
}
public void openTest(Player p) {
        Inventory inv = Bukkit.createInventory(null, 27, ChatColor.GOLD + "Weapons");
        double dmax = 0;
        double dmin = 0;
        String rarity = "";
        double dmax2 = 0;
        double dmin2 = 0;
        String rarity2 = "";
     
        synthDamageT1(dmax, dmin, rarity);
     
        ItemStack woodensword1 = new ItemStack(Material.WOOD_SWORD);
        ItemMeta woodmeta1 = woodensword1.getItemMeta();
        woodmeta1.setDisplayName(ChatColor.WHITE + "Flimsy Wooden Sword");
        ArrayList<String> lore1 = new ArrayList<String>();
        lore1.add(ChatColor.WHITE + "Damage : " + ChatColor.RED + dmin + "-" + dmax);
        lore1.add(ChatColor.WHITE + rarity);
     
        woodmeta1.setLore(lore1);
        woodensword1.setItemMeta(woodmeta1);
        //p.getInventory().addItem(woodensword1);
     
        synthDamageT1(dmax2, dmin2, rarity2);
        ItemStack woodensword2 = new ItemStack(Material.WOOD_SWORD);
        ItemMeta woodmeta2 = woodensword2.getItemMeta();
        woodmeta2.setDisplayName(ChatColor.WHITE + "Basic Wooden Sword");
        ArrayList<String> lore2 = new ArrayList<String>();
        lore2.add(ChatColor.WHITE + "Damage : " + ChatColor.RED + dmin2 + "-" + dmax2);
        lore2.add(ChatColor.WHITE + rarity2);
        woodmeta2.setLore(lore2);
        woodensword2.setItemMeta(woodmeta2);
     
        inv.setItem(10, woodensword1);
        inv.setItem(12, woodensword2);
        p.openInventory(inv);
    }

https://pastebin.com/fe92Dg5F

 

bump please help i cant figure it out

 

solved but i have another issue, it was very different than what i have now so i will post that in new thread