i think im done now?

src/main/java/me/fivevl/doublejump/JumpCommand.java

@@ -6,21 +6,26 @@ import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
+import java.sql.SQLException;
 
 public class JumpCommand implements CommandExecutor {
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, @NotNull String[] args) {
         if (!(sender instanceof Player)) {
-            sender.sendMessage("Only players can use this command!");
+            sender.sendMessage(Main.color("&cOnly players can use this command!"));
             return true;
         }
         Player p = (Player) sender;
         if (!p.hasPermission("doublejump.gui")) {
-            p.sendMessage("You don't have permission to use this command!");
+            p.sendMessage(Main.color("You don't have permission to use this command!"));
             return true;
         }
-        p.openInventory(JumpGui.getGui(p));
+        try {
-        Main.inGui.add(p);
+            p.openInventory(JumpGui.getGui(p));
+            Main.inGui.add(p);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
         return true;
     }
 }

src/main/java/me/fivevl/doublejump/Main.java

@@ -1,18 +1,22 @@
 package me.fivevl.doublejump;
 
 import me.fivevl.doublejump.events.OnFly;
+import me.fivevl.doublejump.events.OnInventoryClick;
+import me.fivevl.doublejump.events.OnJoin;
 import me.fivevl.doublejump.events.OnJump;
 import org.bukkit.Bukkit;
+import org.bukkit.ChatColor;
 import org.bukkit.configuration.ConfigurationSection;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.java.JavaPlugin;
 import java.sql.SQLException;
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Objects;
 
 public class Main extends JavaPlugin {
-    public static List<Player> doDoubleJump = new ArrayList<>();
+    public static HashMap<Player, Integer> doDoubleJump = new HashMap<>();
     public static List<Player> inGui = new ArrayList<>();
     private static Main instance;
     public static Main getInstance() {
@@ -34,6 +38,8 @@ public class Main extends JavaPlugin {
         }
         Bukkit.getPluginManager().registerEvents(new OnFly(), this);
         Bukkit.getPluginManager().registerEvents(new OnJump(), this);
+        Bukkit.getPluginManager().registerEvents(new OnJoin(), this);
+        Bukkit.getPluginManager().registerEvents(new OnInventoryClick(), this);
         Objects.requireNonNull(getCommand("jump")).setExecutor(new JumpCommand());
         getLogger().info("DoubleJump enabled!");
     }
@@ -73,4 +79,8 @@ public class Main extends JavaPlugin {
         sql.connect();
         sql.execute("CREATE TABLE IF NOT EXISTS `settings` (`uuid` VARCHAR(36) NOT NULL, `strength` DOUBLE NOT NULL DEFAULT '1', PRIMARY KEY (`uuid`))");
     }
+
+    public static String color(String s) {
+        return ChatColor.translateAlternateColorCodes('&', s);
+    }
 }

src/main/java/me/fivevl/doublejump/MySQL.java

@@ -1,6 +1,7 @@
 package me.fivevl.doublejump;
 
 import javax.sql.rowset.CachedRowSet;
+import javax.sql.rowset.RowSetProvider;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
@@ -56,7 +57,7 @@ public class MySQL implements Database {
 
     @Override
     public CachedRowSet query(String query) throws SQLException{
-        CachedRowSet cachedRowSet = new com.sun.rowset.CachedRowSetImpl();
+        CachedRowSet cachedRowSet = RowSetProvider.newFactory().createCachedRowSet();
         cachedRowSet.populate(connection.prepareStatement(query).executeQuery());
         return cachedRowSet;
     }

src/main/java/me/fivevl/doublejump/events/OnFly.java

@@ -1,20 +1,28 @@
 package me.fivevl.doublejump.events;
 
 import me.fivevl.doublejump.Main;
+import org.bukkit.Bukkit;
 import org.bukkit.GameMode;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerToggleFlightEvent;
 
+import javax.sql.rowset.CachedRowSet;
+import java.sql.SQLException;
+
 public class OnFly implements Listener {
     @EventHandler
-    public void onFly(PlayerToggleFlightEvent e) {
+    public void onFly(PlayerToggleFlightEvent e) throws SQLException {
         Player p = e.getPlayer();
-        if (p.hasPermission("doublejump.use") && Main.doDoubleJump.contains(p) && (p.getGameMode() == GameMode.ADVENTURE || p.getGameMode() == GameMode.SURVIVAL)) {
+        if (p.hasPermission("doublejump.use") && Main.doDoubleJump.containsKey(p) && (p.getGameMode() == GameMode.ADVENTURE || p.getGameMode() == GameMode.SURVIVAL)) {
             e.setCancelled(true);
             p.setAllowFlight(false);
-            p.setVelocity(p.getLocation().getDirection().multiply(2.0D));
+            Bukkit.getScheduler().cancelTask(Main.doDoubleJump.get(p));
+            Main.doDoubleJump.remove(p);
+            CachedRowSet rs = Main.getMySQL().query("SELECT * FROM `settings` WHERE `uuid` = '" + p.getUniqueId() + "'");
+            rs.next();
+            p.setVelocity(p.getLocation().getDirection().multiply(rs.getDouble("strength")));
             p.setFallDistance(0);
         }
     }

src/main/java/me/fivevl/doublejump/events/OnInventoryClick.java

@@ -0,0 +1,51 @@
+package me.fivevl.doublejump.events;
+
+import me.fivevl.doublejump.Main;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+
+import javax.sql.rowset.CachedRowSet;
+import java.math.RoundingMode;
+import java.sql.SQLException;
+import java.text.DecimalFormat;
+import java.util.Collections;
+
+public class OnInventoryClick implements Listener {
+    @SuppressWarnings("deprecation")
+    @EventHandler
+    public void onClick(InventoryClickEvent e) throws SQLException {
+        Player p = (Player) e.getWhoClicked();
+        if (!Main.inGui.contains(p)) return;
+        e.setCancelled(true);
+        CachedRowSet rs = Main.getMySQL().query("SELECT * FROM `settings` WHERE `uuid` = '" + p.getUniqueId() + "'");
+        rs.next();
+        double strength = rs.getDouble("strength");
+        double newStrength = strength;
+        if (e.getRawSlot() == 12) newStrength = strength - 0.2;
+        if (e.getRawSlot() == 14) newStrength = strength + 0.2;
+        if (newStrength < 1) newStrength = 1;
+        if (newStrength > 5) newStrength = 5;
+        if (strength == newStrength) return;
+        DecimalFormat df = new DecimalFormat("#.#");
+        df.setRoundingMode(RoundingMode.CEILING);
+        newStrength = Double.parseDouble(df.format(newStrength).replace(",", "."));
+        Inventory inv = e.getClickedInventory();
+        ItemStack item = inv.getItem(13);
+        ItemMeta currentStrengthMeta = item.getItemMeta();
+        currentStrengthMeta.setLore(Collections.singletonList(Main.color("&e" + newStrength)));
+        item.setItemMeta(currentStrengthMeta);
+        inv.setItem(13, item);
+        Main.getMySQL().execute("UPDATE `settings` SET `strength` = '" + newStrength + "' WHERE `uuid` = '" + p.getUniqueId() + "'");
+    }
+
+    @EventHandler
+    public void onClose(InventoryCloseEvent e) {
+        Main.inGui.remove((Player) e.getPlayer());
+    }
+}

src/main/java/me/fivevl/doublejump/events/OnJoin.java

@@ -0,0 +1,20 @@
+package me.fivevl.doublejump.events;
+
+import me.fivevl.doublejump.Main;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import javax.sql.rowset.CachedRowSet;
+import java.sql.SQLException;
+
+public class OnJoin implements Listener {
+    @EventHandler
+    public void onJoin(PlayerJoinEvent e) throws SQLException {
+        Player p = e.getPlayer();
+        CachedRowSet rs = Main.getMySQL().query("SELECT * FROM `settings` WHERE `uuid` = '" + p.getUniqueId() + "'");
+        if (!rs.next()) {
+            Main.getMySQL().execute("INSERT INTO `settings` (`uuid`, `strength`) VALUES ('" + p.getUniqueId() + "', default)");
+        }
+    }
+}

src/main/java/me/fivevl/doublejump/events/OnJump.java

@@ -14,11 +14,11 @@ public class OnJump implements Listener {
         Player p = e.getPlayer();
         if (p.hasPermission("doublejump.use") && (p.getGameMode() == GameMode.ADVENTURE || p.getGameMode() == GameMode.SURVIVAL)) {
             p.setAllowFlight(true);
-            Main.doDoubleJump.add(p);
+            int id = Bukkit.getScheduler().scheduleSyncDelayedTask(Main.getInstance(), () -> {
-            Bukkit.getScheduler().scheduleSyncDelayedTask(Main.getInstance(), () -> {
                 p.setAllowFlight(false);
                 Main.doDoubleJump.remove(p);
             }, 20L);
+            Main.doDoubleJump.put(p, id);
         }
     }
 }

src/main/java/me/fivevl/doublejump/guis/JumpGui.java

@@ -1,13 +1,51 @@
 package me.fivevl.doublejump.guis;
 
+import me.fivevl.doublejump.Main;
 import org.bukkit.Bukkit;
+import org.bukkit.Material;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+
+import javax.sql.rowset.CachedRowSet;
+import java.sql.SQLException;
+import java.util.Collections;
 
 public class JumpGui {
     @SuppressWarnings("deprecation")
-    public static Inventory getGui(Player p) {
+    public static Inventory getGui(Player p) throws SQLException {
-        Inventory inv = Bukkit.createInventory(null, 27, "Jump Strength");
+        Inventory inv = Bukkit.createInventory(null, 27, Main.color("&8Jump Strength Menu"));
+        ItemStack glass = new ItemStack(Material.GRAY_STAINED_GLASS_PANE, 1);
+        ItemMeta glassMeta = glass.getItemMeta();
+        glassMeta.setDisplayName(" ");
+        glass.setItemMeta(glassMeta);
+        for (int i = 0; i < inv.getSize(); i++) {
+            inv.setItem(i, glass);
+        }
+
+        ItemStack decreaseStrength = new ItemStack(Material.ARROW, 1);
+        ItemMeta decreaseStrengthMeta = decreaseStrength.getItemMeta();
+        decreaseStrengthMeta.setDisplayName(Main.color("&9Decrease Strength"));
+        decreaseStrength.setItemMeta(decreaseStrengthMeta);
+        inv.setItem(12, decreaseStrength);
+
+        ItemStack increaseStrength = new ItemStack(Material.ARROW, 1);
+        ItemMeta increaseStrengthMeta = increaseStrength.getItemMeta();
+        increaseStrengthMeta.setDisplayName(Main.color("&9Increase Strength"));
+        increaseStrength.setItemMeta(increaseStrengthMeta);
+        inv.setItem(14, increaseStrength);
+
+
+        CachedRowSet rs = Main.getMySQL().query("SELECT * FROM `settings` WHERE `uuid` = '" + p.getUniqueId() + "'");
+        if (rs.next()) {
+            ItemStack currentStrength = new ItemStack(Material.FEATHER, 1);
+            ItemMeta currentStrengthMeta = currentStrength.getItemMeta();
+            currentStrengthMeta.setDisplayName(Main.color("&2Current Jump Strength"));
+            currentStrengthMeta.setLore(Collections.singletonList(Main.color("&e" + rs.getDouble("strength"))));
+            currentStrength.setItemMeta(currentStrengthMeta);
+            inv.setItem(13, currentStrength);
+        }
 
         return inv;
     }