jump gui command

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

@@ -0,0 +1,26 @@
+package me.fivevl.doublejump;
+
+import me.fivevl.doublejump.guis.JumpGui;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+
+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!");
+            return true;
+        }
+        Player p = (Player) sender;
+        if (!p.hasPermission("doublejump.gui")) {
+            p.sendMessage("You don't have permission to use this command!");
+            return true;
+        }
+        p.openInventory(JumpGui.getGui(p));
+        Main.inGui.add(p);
+        return true;
+    }
+}

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

@@ -9,9 +9,11 @@ import org.bukkit.plugin.java.JavaPlugin;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 public class Main extends JavaPlugin {
     public static List<Player> doDoubleJump = new ArrayList<>();
+    public static List<Player> inGui = new ArrayList<>();
     private static Main instance;
     public static Main getInstance() {
         return instance;
@@ -23,6 +25,7 @@ public class Main extends JavaPlugin {
     @Override
     public void onEnable() {
         instance = this;
+        saveDefaultConfig();
         sql = new MySQL();
         try {
             setupDatabase();
@@ -31,6 +34,7 @@ public class Main extends JavaPlugin {
         }
         Bukkit.getPluginManager().registerEvents(new OnFly(), this);
         Bukkit.getPluginManager().registerEvents(new OnJump(), this);
+        Objects.requireNonNull(getCommand("jump")).setExecutor(new JumpCommand());
         getLogger().info("DoubleJump enabled!");
     }
 

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

@@ -19,7 +19,9 @@ public class MySQL implements Database {
 
     @Override
     public void disconnect() throws SQLException {
-        connection.close();
+        if (isConnected()) {
+            connection.close();
+        }
     }
 
     @Override

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

@@ -0,0 +1,14 @@
+package me.fivevl.doublejump.guis;
+
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.Inventory;
+
+public class JumpGui {
+    @SuppressWarnings("deprecation")
+    public static Inventory getGui(Player p) {
+        Inventory inv = Bukkit.createInventory(null, 27, "Jump Strength");
+
+        return inv;
+    }
+}

src/main/resources/config.yml

@@ -1,6 +1,6 @@
 database: # Database configuration, please change it to a valid one.
   host: "12.34.56.78"
-  port: 3306
+  port: "3306"
   username: "admin"
   password: "password"
   database: "database"