Client-side shop items

All shop items are now spawned with packets and reflection client-side, so probably duplicated items are history (finally). This also allowed me to remove the ClearLag and LWC dependency, as ClearLag can't remove client-side items and LWC's Magnet Sucker can't suck them inside a chest. I also changed a bit in the classes of the nms package, so all required classes have to be found before attempting to do anything.

Fixes #11 and fixes #4

pom.xml

@@ -24,10 +24,6 @@
             <id>spigot-repo</id>
             <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
         </repository>
-        <repository>
-            <id>shopchest-repo</id>
-            <url>https://epicericee.github.io/ShopChest/maven/</url>
-        </repository>
         <repository>
             <id>vault-repo</id>
             <url>http://nexus.hc.to/content/repositories/pub_releases/</url>
@@ -41,25 +37,12 @@
             <version>1.10.2-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
-
         <dependency>
             <groupId>net.milkbowl.vault</groupId>
             <artifactId>VaultAPI</artifactId>
             <version>1.6</version>
             <scope>provided</scope>
         </dependency>
-        <dependency>
-            <groupId>me.minebuilders</groupId>
-            <artifactId>clearlag</artifactId>
-            <version>2.9.1</version>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.griefcraft.lwc</groupId>
-            <artifactId>lwc-entity-locking</artifactId>
-            <version>1.7.3</version>
-            <scope>provided</scope>
-        </dependency>
     </dependencies>
 
     <distributionManagement>

src/main/java/de/epiceric/shopchest/ShopChest.java

@@ -22,9 +22,6 @@ import de.epiceric.shopchest.utils.Utils;
 import net.milkbowl.vault.economy.Economy;
 import net.milkbowl.vault.permission.Permission;
 import org.bukkit.Bukkit;
-import org.bukkit.World;
-import org.bukkit.entity.Entity;
-import org.bukkit.entity.Item;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.RegisteredServiceProvider;
 import org.bukkit.plugin.java.JavaPlugin;
@@ -41,7 +38,6 @@ public class ShopChest extends JavaPlugin {
     private Config config = null;
     private Economy econ = null;
     private Permission perm = null;
-    private boolean lwc = false;
     private Database database;
     private boolean isUpdateNeeded = false;
     private String latestVersion = "";
@@ -238,8 +234,6 @@ public class ShopChest extends JavaPlugin {
             }, config.auto_reload_time * 20, config.auto_reload_time * 20);
         }
 
-        lwc = getServer().getPluginManager().isPluginEnabled("LWC");
-
         Bukkit.getScheduler().runTaskAsynchronously(this, new Runnable() {
             @Override
             public void run() {
@@ -254,7 +248,7 @@ public class ShopChest extends JavaPlugin {
                     Bukkit.getConsoleSender().sendMessage("[ShopChest] " + LanguageUtils.getMessage(LocalizedMessage.Message.UPDATE_AVAILABLE, new LocalizedMessage.ReplacedRegex(Regex.VERSION, latestVersion)));
 
                     for (Player p : getServer().getOnlinePlayers()) {
-                        if (p.isOp() || perm.has(p, "shopchest.notification.update")) {
+                        if (perm.has(p, "shopchest.notification.update")) {
                             JsonBuilder jb = new JsonBuilder(ShopChest.this, LanguageUtils.getMessage(LocalizedMessage.Message.UPDATE_AVAILABLE, new LocalizedMessage.ReplacedRegex(Regex.VERSION, latestVersion)), LanguageUtils.getMessage(LocalizedMessage.Message.UPDATE_CLICK_TO_DOWNLOAD), downloadLink);
                             jb.sendJson(p);
                         }
@@ -287,16 +281,10 @@ public class ShopChest extends JavaPlugin {
 
         debug("Registering listeners...");
         getServer().getPluginManager().registerEvents(new HologramUpdateListener(this), this);
-        getServer().getPluginManager().registerEvents(new ItemProtectListener(this), this);
+        getServer().getPluginManager().registerEvents(new ShopItemListener(this), this);
         getServer().getPluginManager().registerEvents(new ShopInteractListener(this), this);
         getServer().getPluginManager().registerEvents(new NotifyUpdateOnJoinListener(this), this);
         getServer().getPluginManager().registerEvents(new ChestProtectListener(this), this);
-        getServer().getPluginManager().registerEvents(new ItemCustomNameListener(), this);
-
-        if (getServer().getPluginManager().isPluginEnabled("ClearLag"))
-            getServer().getPluginManager().registerEvents(new ClearLagListener(), this);
-
-        if (lwc) new LWCMagnetListener(this).initializeListener();
     }
 
     @Override
@@ -314,38 +302,6 @@ public class ShopChest extends JavaPlugin {
             }
         }
 
-        for (World world : Bukkit.getWorlds()) {
-            for (Entity entity : world.getEntities()) {
-                if (entity instanceof Item) {
-                    Item item = (Item) entity;
-                    if (item.hasMetadata("shopItem")) {
-                        if (item.isValid()) {
-                            debug("Removing not removed shop item (#" +
-                                    (item.hasMetadata("shopId") ? item.getMetadata("shopId").get(0).asString() : "?") + ")");
-
-                            item.remove();
-                        }
-                    }
-                }
-            }
-        }
-
-        if (config.enable_debug_log) {
-            for (World world : Bukkit.getWorlds()) {
-                for (Entity entity : world.getEntities()) {
-                    if (entity instanceof Item) {
-                        Item item = (Item) entity;
-                        if (item.hasMetadata("shopItem")) {
-                            if (item.isValid()) {
-                                debug("Shop item still valid (#" +
-                                        (item.hasMetadata("shopId") ? item.getMetadata("shopId").get(0).asString() : "?") + ")");
-                            }
-                        }
-                    }
-                }
-            }
-        }
-
         database.disconnect();
 
         if (fw != null && config.enable_debug_log) {
@@ -426,13 +382,6 @@ public class ShopChest extends JavaPlugin {
         return database;
     }
 
-    /**
-     * @return Whether LWC is available
-     */
-    public boolean hasLWC() {
-        return lwc;
-    }
-
     /**
      * @return Whether an update is needed (will return false if not checked)
      */

src/main/java/de/epiceric/shopchest/listeners/ClearLagListener.java

@@ -1,25 +0,0 @@
-package de.epiceric.shopchest.listeners;
-
-import me.minebuilders.clearlag.events.EntityRemoveEvent;
-import org.bukkit.entity.Entity;
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-
-import java.util.ArrayList;
-
-public class ClearLagListener implements Listener {
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onEntityRemove(EntityRemoveEvent e) {
-        ArrayList<Entity> entityList = new ArrayList<>(e.getEntityList());
-
-        for (Entity entity : entityList) {
-            if (entity.hasMetadata("shopItem")) {
-                e.getEntityList().remove(entity);
-            }
-        }
-    }
-
-
-}

src/main/java/de/epiceric/shopchest/listeners/ItemCustomNameListener.java

@@ -1,17 +0,0 @@
-package de.epiceric.shopchest.listeners;
-
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-import org.bukkit.event.entity.ItemSpawnEvent;
-
-public class ItemCustomNameListener implements Listener {
-
-    @EventHandler(priority = EventPriority.MONITOR)
-    public void onItemSpawn(ItemSpawnEvent e) {
-        if (e.getEntity().hasMetadata("shopItem")) {
-            e.getEntity().setCustomNameVisible(false);
-        }
-    }
-
-}

src/main/java/de/epiceric/shopchest/listeners/ItemProtectListener.java

@@ -1,134 +0,0 @@
-package de.epiceric.shopchest.listeners;
-
-
-import de.epiceric.shopchest.ShopChest;
-import de.epiceric.shopchest.utils.ShopUtils;
-import de.epiceric.shopchest.utils.Utils;
-import org.bukkit.block.Block;
-import org.bukkit.block.BlockFace;
-import org.bukkit.block.BlockState;
-import org.bukkit.entity.Item;
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-import org.bukkit.event.block.*;
-import org.bukkit.event.entity.ItemDespawnEvent;
-import org.bukkit.event.inventory.InventoryPickupItemEvent;
-import org.bukkit.event.player.PlayerBucketEmptyEvent;
-import org.bukkit.event.player.PlayerFishEvent;
-import org.bukkit.event.player.PlayerPickupItemEvent;
-
-import java.lang.reflect.InvocationTargetException;
-
-public class ItemProtectListener implements Listener {
-
-    private ShopUtils shopUtils;
-    private ShopChest plugin;
-
-    public ItemProtectListener(ShopChest plugin) {
-        this.plugin = plugin;
-        this.shopUtils = plugin.getShopUtils();
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onItemDespawn(ItemDespawnEvent e) {
-        Item item = e.getEntity();
-        if (item.hasMetadata("shopItem")) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onPlayerPickUpItem(PlayerPickupItemEvent e) {
-        if (e.getItem().hasMetadata("shopItem")) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onItemPickup(InventoryPickupItemEvent e) {
-        if (e.getItem().hasMetadata("shopItem")) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onBlockPlace(BlockPlaceEvent e) {
-        Block b = e.getBlockPlaced();
-        Block below = b.getRelative(BlockFace.DOWN);
-
-        if (shopUtils.isShop(below.getLocation())) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onMultiBlockPlace(BlockMultiPlaceEvent e) {
-        for (BlockState blockState : e.getReplacedBlockStates()) {
-            Block below = blockState.getBlock().getRelative(BlockFace.DOWN);
-            if (shopUtils.isShop(below.getLocation())) e.setCancelled(true);
-        }
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onPistonExtend(BlockPistonExtendEvent e) {
-        // If the piston would only move itself
-        Block airAfterPiston = e.getBlock().getRelative(e.getDirection());
-        Block belowAir = airAfterPiston.getRelative(BlockFace.DOWN);
-        if (shopUtils.isShop(belowAir.getLocation())) {
-            e.setCancelled(true);
-            return;
-        }
-
-        for (Block b : e.getBlocks()) {
-            Block newBlock = b.getRelative(e.getDirection());
-            Block belowNewBlock = newBlock.getRelative(BlockFace.DOWN);
-            if (shopUtils.isShop(belowNewBlock.getLocation())) e.setCancelled(true);
-        }
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onPistonRetract(BlockPistonRetractEvent e) {
-        for (Block b : e.getBlocks()) {
-            Block newBlock = b.getRelative(e.getDirection());
-            Block belowNewBlock = newBlock.getRelative(BlockFace.DOWN);
-            if (shopUtils.isShop(belowNewBlock.getLocation())) e.setCancelled(true);
-        }
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onLiquidFlow(BlockFromToEvent e) {
-        Block b = e.getToBlock();
-        Block below = b.getRelative(BlockFace.DOWN);
-
-        if (shopUtils.isShop(below.getLocation())) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onBucketEmpty(PlayerBucketEmptyEvent e) {
-        Block b = e.getBlockClicked();
-
-        if (shopUtils.isShop(b.getLocation())) e.setCancelled(true);
-    }
-
-    @EventHandler(priority = EventPriority.HIGH)
-    public void onPlayerFish(PlayerFishEvent e) {
-        if (e.getState() == PlayerFishEvent.State.CAUGHT_ENTITY) {
-            if (e.getCaught() instanceof Item) {
-                Item item = (Item) e.getCaught();
-                if (item.hasMetadata("shopItem")) {
-                    plugin.debug(e.getPlayer().getName() + " tried to fish a shop item");
-                    e.setCancelled(true);
-
-                    // Use some reflection to get the EntityFishingHook class so the hook can be removed...
-                    try {
-                        Class<?> craftFishClass = Class.forName("org.bukkit.craftbukkit." + Utils.getServerVersion() + ".entity.CraftFish");
-                        Object craftFish = craftFishClass.cast(e.getHook());
-
-                        Class<?> entityFishingHookClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".EntityFishingHook");
-                        Object entityFishingHook = craftFishClass.getDeclaredMethod("getHandle").invoke(craftFish);
-
-                        entityFishingHookClass.getDeclaredMethod("die").invoke(entityFishingHook);
-                    } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException | ClassNotFoundException ex) {
-                        plugin.debug("Failed to kill fishing hook with reflection");
-                        plugin.debug(ex);
-                        ex.printStackTrace();
-                    }
-                }
-            }
-        }
-    }
-
-}

src/main/java/de/epiceric/shopchest/listeners/LWCMagnetListener.java

@@ -1,39 +0,0 @@
-package de.epiceric.shopchest.listeners;
-
-import com.griefcraft.lwc.LWC;
-import com.griefcraft.scripting.JavaModule;
-import com.griefcraft.scripting.event.LWCMagnetPullEvent;
-import de.epiceric.shopchest.ShopChest;
-
-public class LWCMagnetListener {
-
-    private ShopChest plugin;
-
-    public LWCMagnetListener(ShopChest plugin) {
-        this.plugin = plugin;
-    }
-
-    public void initializeListener() {
-        try {
-            Class.forName("com.griefcraft.scripting.event.LWCMagnetPullEvent");
-
-            LWC.getInstance().getModuleLoader().registerModule(ShopChest.getInstance(), new JavaModule() {
-
-                @Override
-                public void onMagnetPull(LWCMagnetPullEvent event) {
-                    if (event.getItem().hasMetadata("shopItem")) {
-                        event.setCancelled(true);
-                    }
-                }
-
-            });
-
-        } catch (ClassNotFoundException ex) {
-            plugin.debug("Using not recommended version of LWC");
-            plugin.getLogger().warning("Shop items can be sucked up by the magnet flag of a protected chest of LWC.");
-            plugin.getLogger().warning("Use 'LWC Unofficial - Entity locking' v1.7.3 or later by 'Me_Goes_RAWR' to prevent this.");
-        }
-    }
-
-
-}

src/main/java/de/epiceric/shopchest/listeners/NotifyUpdateOnJoinListener.java

@@ -27,7 +27,7 @@ public class NotifyUpdateOnJoinListener implements Listener {
         Player p = e.getPlayer();
 
         if (plugin.isUpdateNeeded()) {
-            if (p.isOp() || perm.has(p, "shopchest.notification.update")) {
+            if (perm.has(p, "shopchest.notification.update")) {
                 JsonBuilder jb = new JsonBuilder(plugin, LanguageUtils.getMessage(LocalizedMessage.Message.UPDATE_AVAILABLE, new LocalizedMessage.ReplacedRegex(Regex.VERSION, plugin.getLatestVersion())), LanguageUtils.getMessage(LocalizedMessage.Message.UPDATE_CLICK_TO_DOWNLOAD), plugin.getDownloadLink());
                 jb.sendJson(p);
             }

src/main/java/de/epiceric/shopchest/listeners/ShopItemListener.java

@@ -0,0 +1,126 @@
+package de.epiceric.shopchest.listeners;
+
+import de.epiceric.shopchest.ShopChest;
+import de.epiceric.shopchest.shop.Shop;
+import de.epiceric.shopchest.utils.ShopUtils;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.block.BlockFace;
+import org.bukkit.block.BlockState;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.block.*;
+import org.bukkit.event.player.*;
+
+import java.lang.reflect.InvocationTargetException;
+
+public class ShopItemListener implements Listener {
+
+    private ShopUtils shopUtils;
+    private ShopChest plugin;
+
+    public ShopItemListener(ShopChest plugin) {
+        this.plugin = plugin;
+        this.shopUtils = plugin.getShopUtils();
+    }
+
+    @EventHandler
+    public void onPlayerJoin(PlayerJoinEvent e) {
+        for (Shop shop : plugin.getShopUtils().getShops()) {
+            shop.getItem().setVisible(e.getPlayer(), true);
+        }
+    }
+
+    @EventHandler
+    public void onPlayerLeave(PlayerQuitEvent e) {
+        for (Shop shop : plugin.getShopUtils().getShops()) {
+            shop.getItem().setVisible(e.getPlayer(), false);
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onBlockPlace(BlockPlaceEvent e) {
+        Block b = e.getBlockPlaced();
+        Block below = b.getRelative(BlockFace.DOWN);
+
+        if (shopUtils.isShop(below.getLocation())) {
+            shopUtils.getShop(below.getLocation()).getItem().resetForPlayer(e.getPlayer());
+            e.setCancelled(true);
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onMultiBlockPlace(BlockMultiPlaceEvent e) {
+        for (BlockState blockState : e.getReplacedBlockStates()) {
+            Block below = blockState.getBlock().getRelative(BlockFace.DOWN);
+
+            if (shopUtils.isShop(below.getLocation())) {
+                shopUtils.getShop(below.getLocation()).getItem().resetForPlayer(e.getPlayer());
+                e.setCancelled(true);
+            }
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onPistonExtend(BlockPistonExtendEvent e) {
+        // If the piston would only move itself
+        Block airAfterPiston = e.getBlock().getRelative(e.getDirection());
+        Block belowAir = airAfterPiston.getRelative(BlockFace.DOWN);
+        if (shopUtils.isShop(belowAir.getLocation())) {
+            e.setCancelled(true);
+            return;
+        }
+
+        for (Block b : e.getBlocks()) {
+            Block newBlock = b.getRelative(e.getDirection());
+            Block belowNewBlock = newBlock.getRelative(BlockFace.DOWN);
+            if (shopUtils.isShop(belowNewBlock.getLocation())) e.setCancelled(true);
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onPistonRetract(BlockPistonRetractEvent e) {
+        for (Block b : e.getBlocks()) {
+            Block newBlock = b.getRelative(e.getDirection());
+            Block belowNewBlock = newBlock.getRelative(BlockFace.DOWN);
+            if (shopUtils.isShop(belowNewBlock.getLocation())) {
+                e.setCancelled(true);
+                for (Player p : Bukkit.getOnlinePlayers()) {
+                    shopUtils.getShop(belowNewBlock.getLocation()).getItem().resetForPlayer(p);
+                }
+            }
+        }
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onLiquidFlow(BlockFromToEvent e) {
+        Block b = e.getToBlock();
+        Block below = b.getRelative(BlockFace.DOWN);
+
+        if (shopUtils.isShop(below.getLocation())) e.setCancelled(true);
+    }
+
+    @EventHandler(priority = EventPriority.HIGH)
+    public void onBucketEmpty(PlayerBucketEmptyEvent e) {
+        Block clicked = e.getBlockClicked();
+        Block underWater = clicked.getRelative(BlockFace.DOWN).getRelative(e.getBlockFace());
+
+        if (shopUtils.isShop(clicked.getLocation())) {
+            if (e.getBucket() == Material.LAVA_BUCKET) {
+                shopUtils.getShop(clicked.getLocation()).getItem().resetForPlayer(e.getPlayer());
+            }
+        } else if (shopUtils.isShop(underWater.getLocation())) {
+            if (e.getBucket() == Material.LAVA_BUCKET) {
+                shopUtils.getShop(underWater.getLocation()).getItem().resetForPlayer(e.getPlayer());
+            }
+        } else {
+            return;
+        }
+
+        e.setCancelled(true);
+    }
+
+}

src/main/java/de/epiceric/shopchest/nms/Hologram.java

@@ -13,7 +13,6 @@ import java.util.List;
 
 public class Hologram {
 
-    private Class<?> entityArmorStandClass;
     private boolean exists = false;
     private int count;
     private List<Object> entityList = new ArrayList<>();
@@ -22,19 +21,28 @@ public class Hologram {
     private List<Player> visible = new ArrayList<>();
     private ShopChest plugin;
 
+    private Class<?> entityArmorStandClass = Utils.getNMSClass("EntityArmorStand");
+    private Class<?> nmsWorldClass = Utils.getNMSClass("World");
+    private Class<?> packetPlayOutSpawnEntityLivingClass = Utils.getNMSClass("PacketPlayOutSpawnEntityLiving");
+    private Class<?> packetPlayOutEntityDestroyClass = Utils.getNMSClass("PacketPlayOutEntityDestroy");
+    private Class<?> entityLivingClass = Utils.getNMSClass("EntityLiving");
+
     public Hologram(ShopChest plugin, String[] text, Location location) {
         this.plugin = plugin;
         this.text = text;
         this.location = location;
 
-        try {
+        Class[] requiredClasses = new Class[] {
-            entityArmorStandClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".EntityArmorStand");
+                nmsWorldClass, entityArmorStandClass, entityLivingClass,
-        } catch (ClassNotFoundException e) {
+                packetPlayOutSpawnEntityLivingClass, packetPlayOutEntityDestroyClass,
-            plugin.debug("Could not find EntityArmorStand class");
+        };
-            plugin.debug(e);
+
-            e.printStackTrace();
+        for (Class c : requiredClasses) {
+            if (c == null) {
+                plugin.debug("Failed to create hologram: Could not find all required classes");
                 return;
             }
+        }
 
         create();
     }
@@ -42,8 +50,6 @@ public class Hologram {
     private void create() {
         for (String text : this.text) {
             try {
-                Class<?> nmsWorldClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".World");
-
                 Object craftWorld = this.location.getWorld().getClass().cast(this.location.getWorld());
                 Object nmsWorld = nmsWorldClass.cast(craftWorld.getClass().getMethod("getHandle").invoke(craftWorld));
 
@@ -63,7 +69,7 @@ public class Hologram {
                 entityList.add(entityArmorStand);
                 this.location.subtract(0, 0.25, 0);
                 count++;
-            } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException | InvocationTargetException | InstantiationException e) {
+            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException | InstantiationException e) {
                 plugin.debug("Could not create Hologram with reflection");
                 plugin.debug(e);
                 e.printStackTrace();
@@ -93,14 +99,11 @@ public class Hologram {
     public void showPlayer(Player p) {
         for (Object o : entityList) {
             try {
-                Class<?> packetClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".PacketPlayOutSpawnEntityLiving");
-                Class<?> entityLivingClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".EntityLiving");
-
                 Object entityLiving = entityLivingClass.cast(o);
-                Object packet = packetClass.getConstructor(entityLivingClass).newInstance(entityLiving);
+                Object packet = packetPlayOutSpawnEntityLivingClass.getConstructor(entityLivingClass).newInstance(entityLiving);
 
                 Utils.sendPacket(plugin, packet, p);
-            } catch (NoSuchMethodException | InstantiationException | InvocationTargetException | IllegalAccessException | ClassNotFoundException e) {
+            } catch (NoSuchMethodException | InstantiationException | InvocationTargetException | IllegalAccessException e) {
                 plugin.debug("Could not show Hologram to player with reflection");
                 plugin.debug(e);
                 e.printStackTrace();
@@ -115,14 +118,12 @@ public class Hologram {
     public void hidePlayer(Player p) {
         for (Object o : entityList) {
             try {
-                Class<?> packetClass = Class.forName("net.minecraft.server." + Utils.getServerVersion() + ".PacketPlayOutEntityDestroy");
-
                 int id = (int) entityArmorStandClass.getMethod("getId").invoke(o);
 
-                Object packet = packetClass.getConstructor(int[].class).newInstance((Object) new int[] {id});
+                Object packet = packetPlayOutEntityDestroyClass.getConstructor(int[].class).newInstance((Object) new int[] {id});
 
                 Utils.sendPacket(plugin, packet, p);
-            } catch (NoSuchMethodException | InstantiationException | InvocationTargetException | IllegalAccessException | ClassNotFoundException e) {
+            } catch (NoSuchMethodException | InstantiationException | InvocationTargetException | IllegalAccessException e) {
                 plugin.debug("Could not hide Hologram from player with reflection");
                 plugin.debug(e);
                 e.printStackTrace();

src/main/java/de/epiceric/shopchest/nms/JsonBuilder.java

@@ -15,9 +15,30 @@ public class JsonBuilder {
     private List<String> extras = new ArrayList<>();
     private ShopChest plugin;
 
+    private Class<?> iChatBaseComponentClass = Utils.getNMSClass("IChatBaseComponent");
+    private Class<?> packetPlayOutChatClass = Utils.getNMSClass("PacketPlayOutChat");
+    private Class<?> chatSerializerClass;
+
     public JsonBuilder(ShopChest plugin, String text, String hoverText, String downloadLink) {
         this.plugin = plugin;
 
+        if (Utils.getServerVersion().equals("v1_8_R1")) {
+            chatSerializerClass = Utils.getNMSClass("ChatSerializer");
+        } else {
+            chatSerializerClass = Utils.getNMSClass("ChatBaseComponent$ChatSerializer");
+        }
+
+        Class[] requiredClasses = new Class[] {
+          iChatBaseComponentClass, packetPlayOutChatClass, chatSerializerClass
+        };
+
+        for (Class c : requiredClasses) {
+            if (c == null) {
+                plugin.debug("Failed to instantiate JsonBuilder: Could not find all required classes");
+                return;
+            }
+        }
+
         parse(text, hoverText, downloadLink);
     }
 
@@ -90,24 +111,12 @@ public class JsonBuilder {
 
     public void sendJson(Player p) {
         try {
-            String version = Utils.getServerVersion();
-
-            Class<?> iChatBaseComponentClass = Class.forName("net.minecraft.server." + version + ".IChatBaseComponent");
-            Class<?> packetPlayOutChatClass = Class.forName("net.minecraft.server." + version + ".PacketPlayOutChat");
-            Class<?> chatSerializerClass;
-
-            if (version.equals("v1_8_R1")) {
-                chatSerializerClass = Class.forName("net.minecraft.server." + version + ".ChatSerializer");
-            } else {
-                chatSerializerClass = Class.forName("net.minecraft.server." + version + ".IChatBaseComponent$ChatSerializer");
-            }
-
             Object iChatBaseComponent = chatSerializerClass.getMethod("a", String.class).invoke(null, toString());
             Object packetPlayOutChat = packetPlayOutChatClass.getConstructor(iChatBaseComponentClass).newInstance(iChatBaseComponent);
 
             Utils.sendPacket(plugin, packetPlayOutChat, p);
         } catch (InstantiationException | InvocationTargetException |
-                IllegalAccessException | NoSuchMethodException | ClassNotFoundException e) {
+                IllegalAccessException | NoSuchMethodException e) {
             plugin.debug("Failed to send packet with reflection");
             plugin.debug(e);
             e.printStackTrace();

src/main/java/de/epiceric/shopchest/nms/SpawnEggMeta.java

@@ -11,7 +11,12 @@ public class SpawnEggMeta {
 
     private static String getNBTEntityID(ShopChest plugin, ItemStack stack) {
         try {
-            Class<?> craftItemStackClass = Class.forName("org.bukkit.craftbukkit." + Utils.getServerVersion() + ".inventory.CraftItemStack");
+            Class<?> craftItemStackClass = Utils.getCraftClass("inventory.CraftItemStack");
+
+            if (craftItemStackClass == null) {
+                plugin.debug("Failed to get NBTEntityID: Could not find CraftItemStack class");
+                return null;
+            }
 
             Object nmsStack = craftItemStackClass.getMethod("asNMSCopy", ItemStack.class).invoke(null, stack);
 
@@ -24,7 +29,7 @@ public class SpawnEggMeta {
             Object id = entityTagCompound.getClass().getMethod("getString", String.class).invoke(entityTagCompound, "id");
             if (id instanceof String) return (String) id;
 
-        } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
+        } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
             plugin.debug("Could not get NBTEntityID with reflection");
             plugin.debug(e);
             e.printStackTrace();

src/main/java/de/epiceric/shopchest/shop/Shop.java

@@ -5,7 +5,6 @@ import de.epiceric.shopchest.config.Regex;
 import de.epiceric.shopchest.language.LanguageUtils;
 import de.epiceric.shopchest.language.LocalizedMessage;
 import de.epiceric.shopchest.nms.Hologram;
-import de.epiceric.shopchest.utils.Utils;
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
 import org.bukkit.Material;
@@ -14,15 +13,9 @@ import org.bukkit.block.Block;
 import org.bukkit.block.BlockFace;
 import org.bukkit.block.Chest;
 import org.bukkit.block.DoubleChest;
-import org.bukkit.entity.Item;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.InventoryHolder;
 import org.bukkit.inventory.ItemStack;
-import org.bukkit.inventory.meta.ItemMeta;
-import org.bukkit.metadata.FixedMetadataValue;
-import org.bukkit.util.Vector;
-
-import java.util.UUID;
 
 public class Shop {
 
@@ -32,7 +25,7 @@ public class Shop {
     private ItemStack product;
     private Location location;
     private Hologram hologram;
-    private Item item;
+    private ShopItem item;
     private double buyPrice;
     private double sellPrice;
     private ShopType shopType;
@@ -71,7 +64,7 @@ public class Shop {
         }
 
         if (hologram == null || !hologram.exists()) createHologram();
-        if (item == null || item.isDead()) createItem();
+        if (item == null) createItem();
     }
 
     private Shop(OfflinePlayer vendor, ItemStack product, Location location, double buyPrice, double sellPrice, ShopType shopType) {
@@ -117,25 +110,18 @@ public class Shop {
         if (plugin.getShopChestConfig().show_shop_items) {
             plugin.debug("Creating item (#" + id + ")");
 
-            Item item;
             Location itemLocation;
             ItemStack itemStack;
-            ItemMeta itemMeta = product.getItemMeta();
-            itemMeta.setDisplayName(UUID.randomUUID().toString());
 
             itemLocation = new Location(location.getWorld(), hologram.getLocation().getX(), location.getY() + 1, hologram.getLocation().getZ());
-            itemStack = new ItemStack(product);
+            itemStack = product.clone();
             itemStack.setAmount(1);
-            itemStack.setItemMeta(itemMeta);
 
-            item = location.getWorld().dropItem(itemLocation, itemStack);
+            this.item = new ShopItem(plugin, itemStack, itemLocation);
-            item.setVelocity(new Vector(0, 0, 0));
-            item.setMetadata("shopItem", new FixedMetadataValue(plugin, true));
-            item.setMetadata("shopId", new FixedMetadataValue(plugin, id));
-            item.setCustomNameVisible(false);
-            item.setPickupDelay(Integer.MAX_VALUE);
 
-            this.item = item;
+            for (Player p : Bukkit.getOnlinePlayers()) {
+                item.setVisible(p, true);
+            }
         }
     }
 
@@ -269,6 +255,13 @@ public class Shop {
         return hologram;
     }
 
+    /**
+     * @return Floating {@link ShopItem} of the shop
+     */
+    public ShopItem getItem() {
+        return item;
+    }
+
     /**
      * @return {@link InventoryHolder} of the shop or <b>null</b> if the shop has no chest.
      */

src/main/java/de/epiceric/shopchest/shop/ShopItem.java

@@ -0,0 +1,155 @@
+package de.epiceric.shopchest.shop;
+
+import de.epiceric.shopchest.ShopChest;
+import de.epiceric.shopchest.utils.Utils;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ShopItem {
+
+    private ShopChest plugin;
+    private Map<Player, Boolean> visible = new HashMap<>();
+    private ItemStack itemStack;
+    private Location location;
+
+    private Object entityItem;
+    private int entityId;
+    private Object[] creationPackets = new Object[3];
+
+    private Class<?> nmsWorldClass = Utils.getNMSClass("World");
+    private Class<?> craftWorldClass = Utils.getCraftClass("CraftWorld");
+    private Class<?> nmsItemStackClass = Utils.getNMSClass("ItemStack");
+    private Class<?> craftItemStackClass = Utils.getCraftClass("inventory.CraftItemStack");
+    private Class<?> entityItemClass = Utils.getNMSClass("EntityItem");
+    private Class<?> entityClass = Utils.getNMSClass("Entity");
+    private Class<?> packetPlayOutSpawnEntityClass = Utils.getNMSClass("PacketPlayOutSpawnEntity");
+    private Class<?> packetPlayOutEntityMetadataClass = Utils.getNMSClass("PacketPlayOutEntityMetadata");
+    private Class<?> dataWatcherClass = Utils.getNMSClass("DataWatcher");
+    private Class<?> packetPlayOutEntityDestroyClass = Utils.getNMSClass("PacketPlayOutEntityDestroy");
+    private Class<?> packetPlayOutEntityVelocityClass = Utils.getNMSClass("PacketPlayOutEntityVelocity");
+
+    public ShopItem(ShopChest plugin, ItemStack itemStack, Location location) {
+        this.plugin = plugin;
+        this.itemStack = itemStack;
+        this.location = location;
+
+        Class[] requiredClasses = new Class[] {
+                nmsWorldClass, craftWorldClass, nmsItemStackClass, craftItemStackClass, entityItemClass,
+                packetPlayOutSpawnEntityClass, packetPlayOutEntityMetadataClass, dataWatcherClass,
+                packetPlayOutEntityDestroyClass, entityClass, packetPlayOutEntityVelocityClass,
+        };
+
+        for (Class c : requiredClasses) {
+            if (c == null) {
+                plugin.debug("Failed to create shop item: Could not find all required classes");
+                return;
+            }
+        }
+
+        create();
+    }
+
+    private void create() {
+        try {
+            Object craftWorld = craftWorldClass.cast(location.getWorld());
+            Object nmsWorld = craftWorldClass.getMethod("getHandle").invoke(craftWorld);
+
+            Object nmsItemStack = craftItemStackClass.getMethod("asNMSCopy", ItemStack.class).invoke(null, itemStack);
+
+            Constructor<?> entityItemConstructor = entityItemClass.getConstructor(nmsWorldClass);
+            entityItem = entityItemConstructor.newInstance(nmsWorld);
+
+            entityItemClass.getMethod("setPosition", double.class, double.class, double.class).invoke(entityItem, location.getX(), location.getY(), location.getZ());
+            entityItemClass.getMethod("setItemStack", nmsItemStackClass).invoke(entityItem, nmsItemStack);
+
+            Field ageField = entityItemClass.getDeclaredField("age");
+            ageField.setAccessible(true);
+            ageField.setInt(entityItem, -32768);
+
+            entityId = (int) entityItemClass.getMethod("getId").invoke(entityItem);
+            Object dataWatcher = entityItemClass.getMethod("getDataWatcher").invoke(entityItem);
+
+            creationPackets[0] = packetPlayOutSpawnEntityClass.getConstructor(entityClass, int.class).newInstance(entityItem, 2);
+            creationPackets[1] = packetPlayOutEntityMetadataClass.getConstructor(int.class, dataWatcherClass, boolean.class).newInstance(entityId, dataWatcher, true);
+            creationPackets[2] = packetPlayOutEntityVelocityClass.getConstructor(int.class, double.class, double.class, double.class).newInstance(entityId, 0D, 0D, 0D);
+        } catch (NoSuchMethodException | NoSuchFieldException | InstantiationException | IllegalAccessException | InvocationTargetException e) {
+            plugin.debug("Failed to create shop item with reflection");
+            plugin.debug(e);
+            e.printStackTrace();
+        }
+    }
+
+    public void remove() {
+        for (Player p : visible.keySet()) {
+            if (isVisible(p)) setVisible(p, false);
+        }
+    }
+
+    /**
+     * Respawns the item at the set location for a player
+     * @param p Player, for which the item should be reset
+     */
+    public void resetForPlayer(Player p) {
+        setVisible(p, false);
+        setVisible(p, true);
+    }
+
+    public boolean isVisible(Player p) {
+        return visible.get(p) == null ? false : visible.get(p);
+    }
+
+    public void setVisible(final Player p, boolean visible) {
+        if (this.visible.containsKey(p) && this.visible.get(p) == visible)
+            return;
+
+        if (visible) {
+            for (Object packet : this.creationPackets) {
+                Utils.sendPacket(plugin, packet, p);
+            }
+        } else {
+            try {
+                if (p.isOnline()) {
+                    Object packetPlayOutEntityDestroy = packetPlayOutEntityDestroyClass.getConstructor(int[].class).newInstance((Object) new int[]{entityId});
+                    Utils.sendPacket(plugin, packetPlayOutEntityDestroy, p);
+                }
+            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException | InstantiationException e) {
+                plugin.debug("Failed to destroy shop item with reflection");
+                plugin.debug(e);
+                e.printStackTrace();
+            }
+        }
+
+        this.visible.put(p, visible);
+    }
+
+
+    /**
+     * @return Clone of the location, where the shop item should be (it could have been moved by something, even though it shouldn't)
+     *         To get the exact location, use reflection and extract the location of the {@code EntityItem}
+     *         which you can get in {@link #getEntityItem()}.
+     */
+    public Location getLocation() {
+        return location.clone();
+    }
+
+    /**
+     * @return {@code net.minecraft.server.[VERSION].EntityItem}
+     */
+    public Object getEntityItem() {
+        return entityItem;
+    }
+
+    /**
+     * @return A clone of this Item's {@link ItemStack}
+     */
+    public ItemStack getItemStack() {
+        return itemStack.clone();
+    }
+}

src/main/java/de/epiceric/shopchest/utils/ShopUtils.java

@@ -221,36 +221,6 @@ public class ShopUtils {
             }
         }
 
-        for (World world : Bukkit.getWorlds()) {
-            for (Entity entity : world.getEntities()) {
-                if (entity instanceof Item) {
-                    Item item = (Item) entity;
-                    if (item.hasMetadata("shopItem")) {
-                        if (item.isValid()) {
-                            plugin.debug("Removing not removed shop item (#" +
-                                    (item.hasMetadata("shopId") ? item.getMetadata("shopId").get(0).asString() : "?") + ")");
-
-                            item.remove();
-                        }
-                    }
-                }
-            }
-        }
-
-        for (World world : Bukkit.getWorlds()) {
-            for (Entity entity : world.getEntities()) {
-                if (entity instanceof Item) {
-                    Item item = (Item) entity;
-                    if (item.hasMetadata("shopItem")) {
-                        if (item.isValid()) {
-                            plugin.debug("Shop item still valid (#" +
-                                    (item.hasMetadata("shopId") ? item.getMetadata("shopId").get(0).asString() : "?") + ")");
-                        }
-                    }
-                }
-            }
-        }
-
         int count = 0;
         for (int id = 1; id <= highestId; id++) {
 

src/main/java/de/epiceric/shopchest/utils/Utils.java

@@ -53,6 +53,30 @@ public class Utils {
         return amount;
     }
 
+    /**
+     * @param className Name of the class
+     * @return Class in {@code net.minecraft.server.[VERSION]} package with the specified name or {@code null} if the class was not found
+     */
+    public static Class<?> getNMSClass(String className) {
+        try {
+            return Class.forName("net.minecraft.server." + getServerVersion() + "." + className);
+        } catch (ClassNotFoundException e) {
+            return null;
+        }
+    }
+
+    /**
+     * @param className Name of the class
+     * @return Class in {@code org.bukkit.craftbukkit.[VERSION]} package with the specified name or {@code null} if the class was not found
+     */
+    public static Class<?> getCraftClass(String className) {
+        try {
+            return Class.forName("org.bukkit.craftbukkit." + getServerVersion() + "." + className);
+        } catch (ClassNotFoundException e) {
+            return null;
+        }
+    }
+
     /**
      * Send a packet to a player
      * @param packet Packet to send