diff --git a/pom.xml b/pom.xml
index a14db4a..ada667e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2,7 +2,7 @@
     <groupId>com.songoda</groupId>
     <artifactId>EpicFurnaces</artifactId>
     <modelVersion>4.0.0</modelVersion>
-    <version>4.7.1</version>
+    <version>4.7.2</version>
     <build>
         <defaultGoal>clean install</defaultGoal>
         <finalName>EpicFurnaces-${project.version}</finalName>
@@ -41,7 +41,7 @@
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-shade-plugin</artifactId>
-                <version>3.1.0</version>
+                <version>3.3.0-SNAPSHOT</version>
                 <executions>
                     <execution>
                         <id>shaded</id>
@@ -79,6 +79,12 @@
             </plugin>
         </plugins>
     </build>
+    <pluginRepositories>
+        <pluginRepository>
+            <id>apache.snapshots</id>
+            <url>https://repository.apache.org/snapshots/</url>
+        </pluginRepository>
+    </pluginRepositories>
     <repositories>
         <repository>
             <id>public</id>
@@ -89,7 +95,7 @@
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot</artifactId>
-            <version>1.16.1</version>
+            <version>1.17</version>
         </dependency>
         <dependency>
             <groupId>com.songoda</groupId>
diff --git a/src/main/java/com/songoda/epicfurnaces/EpicFurnaces.java b/src/main/java/com/songoda/epicfurnaces/EpicFurnaces.java
index 6de341f..4d2ea96 100644
--- a/src/main/java/com/songoda/epicfurnaces/EpicFurnaces.java
+++ b/src/main/java/com/songoda/epicfurnaces/EpicFurnaces.java
@@ -56,6 +56,8 @@ import org.bukkit.plugin.PluginManager;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -63,7 +65,7 @@ import java.util.Map;
 import java.util.UUID;
 import java.util.stream.Collectors;
 
-public class  EpicFurnaces extends SongodaPlugin {
+public class EpicFurnaces extends SongodaPlugin {
 
     private static EpicFurnaces INSTANCE;
 
@@ -247,14 +249,6 @@ public class  EpicFurnaces extends SongodaPlugin {
 
     @Override
     public void onDataLoad() {
-        // Register Hologram Plugin
-
-        if (Settings.HOLOGRAMS.getBoolean()) {
-            for (Furnace furnace : getFurnaceManager().getFurnaces().values()) {
-                if (furnace.getLocation() == null || furnace.getLocation().getWorld() == null)
-                    continue;
-            }
-        }
     }
 
     @Override
@@ -267,67 +261,70 @@ public class  EpicFurnaces extends SongodaPlugin {
 
     @Override
     public List<Config> getExtraConfig() {
-        return Arrays.asList(levelsFile);
+        return Collections.singletonList(levelsFile);
     }
 
     public void clearHologram(Furnace furnace) {
         HologramManager.removeHologram(furnace.getLocation().add(0, .15, 0));
     }
 
-    public void updateHologram(Furnace furnace) {
+    public void updateHolograms(Collection<Furnace> furnaces) {
         // are holograms enabled?
         if (!Settings.HOLOGRAMS.getBoolean() || !HologramManager.getManager().isEnabled()) return;
-        // don't try to load furnaces in chunks that aren't loaded
-        if (!furnace.isInLoadedChunk()) return;
 
-        BlockState state = furnace.getLocation().getBlock().getState();
+        Map<Location, List<String>> holograms = new HashMap<>(furnaces.size());
 
-        // verify that this is a furnace
-        if (!(state instanceof org.bukkit.block.Furnace)) return;
+        for (Furnace furnace : furnaces) {
+            // don't try to load furnaces in chunks that aren't loaded
+            if (!furnace.isInLoadedChunk()) continue;
 
-        org.bukkit.block.Furnace furnaceBlock = ((org.bukkit.block.Furnace) state);
+            BlockState state = furnace.getLocation().getBlock().getState();
 
-        int performance = (furnaceBlock.getCookTime() - furnace.getPerformanceTotal(furnaceBlock.getType())) <= 0 ? 0 : furnace.getPerformanceTotal(furnaceBlock.getType());
+            // verify that this is a furnace
+            if (!(state instanceof org.bukkit.block.Furnace)) continue;
 
-        float percent = (float) (furnaceBlock.getCookTime() - performance) / (200 - performance);
+            org.bukkit.block.Furnace furnaceBlock = ((org.bukkit.block.Furnace) state);
 
-        int progressBars = (int) (6 * percent) + (percent == 0 ? 0 : 1);
-        int leftOver = (6 - progressBars);
+            int performance = (furnaceBlock.getCookTime() - furnace.getPerformanceTotal(furnaceBlock.getType())) <= 0 ? 0 : furnace.getPerformanceTotal(furnaceBlock.getType());
+            float percent = (float) (furnaceBlock.getCookTime() - performance) / (200 - performance);
 
-        StringBuilder sb = new StringBuilder();
-        for (int i = 0; i < progressBars; i++) {
-            sb.append("&a=");
-        }
-        for (int i = 0; i < leftOver; i++) {
-            sb.append("&c=");
+            int progressBars = (int) (6 * percent) + (percent == 0 ? 0 : 1);
+            int leftOver = (6 - progressBars);
+
+            String progress;
+
+            if (furnaceBlock.getInventory().getFuel() != null) {
+                StringBuilder sb = new StringBuilder();
+                for (int i = 0; i < progressBars; i++) {
+                    sb.append("&a=");
+                }
+                for (int i = 0; i < leftOver; i++) {
+                    sb.append("&c=");
+                }
+
+                progress = Methods.formatText(sb.toString());
+            } else {
+                progress = getLocale().getMessage("general.hologram.outoffuel").getMessage();
+            }
+
+            int inAmt = 0;
+            int outAmt = 0;
+            if (furnaceBlock.getInventory().getSmelting() != null) {
+                inAmt = furnaceBlock.getInventory().getSmelting().getAmount();
+            }
+            if (furnaceBlock.getInventory().getResult() != null) {
+                outAmt = furnaceBlock.getInventory().getResult().getAmount();
+            }
+
+            String stats = getLocale().getMessage("general.hologram.stats")
+                    .processPlaceholder("in", inAmt)
+                    .processPlaceholder("out", Math.min(outAmt, 64)).getMessage();
+
+            holograms.put(furnace.getLocation().add(0, .15, 0), Arrays.asList(progress, stats));
         }
 
-        ArrayList<String> lines = new ArrayList<>();
-
-        String progress = Methods.formatText(sb.toString());
-
-        if (furnaceBlock.getInventory().getFuel() == null) {
-            progress = getLocale().getMessage("general.hologram.outoffuel").getMessage();
-        }
-
-        int inAmt = 0;
-        int outAmt = 0;
-        if (furnaceBlock.getInventory().getSmelting() != null) {
-            inAmt = furnaceBlock.getInventory().getSmelting().getAmount();
-        }
-        if (furnaceBlock.getInventory().getResult() != null) {
-            outAmt = furnaceBlock.getInventory().getResult().getAmount();
-        }
-
-        String stats = getLocale().getMessage("general.hologram.stats")
-                .processPlaceholder("in", inAmt)
-                .processPlaceholder("out", Math.min(outAmt, 64)).getMessage();
-
-        lines.add(progress);
-        lines.add(stats);
-
-        // create the hologram
-        HologramManager.updateHologram(furnace.getLocation().add(0, .15, 0), lines);
+        // Update holograms
+        HologramManager.bulkUpdateHolograms(holograms);
     }
 
     private void loadLevelManager() {
@@ -424,7 +421,7 @@ public class  EpicFurnaces extends SongodaPlugin {
 
         // Legacy trash.
         if (item.getItemMeta().getDisplayName().contains(":")) {
-            String arr[] = (item.getItemMeta().getDisplayName().replace("§", "")).split(":");
+            String[] arr = (item.getItemMeta().getDisplayName().replace("§", "")).split(":");
             return Integer.parseInt(arr[0]);
         } else {
             return 1;
@@ -440,7 +437,7 @@ public class  EpicFurnaces extends SongodaPlugin {
 
         // Legacy trash.
         if (item.getItemMeta().getDisplayName().contains(":")) {
-            String arr[] = (item.getItemMeta().getDisplayName().replace("§", "")).split(":");
+            String[] arr = (item.getItemMeta().getDisplayName().replace("§", "")).split(":");
             return Integer.parseInt(arr[1]);
         } else {
             return 0;
diff --git a/src/main/java/com/songoda/epicfurnaces/furnace/Furnace.java b/src/main/java/com/songoda/epicfurnaces/furnace/Furnace.java
index 18a3956..6826844 100644
--- a/src/main/java/com/songoda/epicfurnaces/furnace/Furnace.java
+++ b/src/main/java/com/songoda/epicfurnaces/furnace/Furnace.java
@@ -4,6 +4,7 @@ import com.songoda.core.compatibility.CompatibleMaterial;
 import com.songoda.core.compatibility.ServerVersion;
 import com.songoda.core.gui.GuiManager;
 import com.songoda.core.hooks.EconomyManager;
+import com.songoda.core.math.MathUtils;
 import com.songoda.core.hooks.ProtectionManager;
 import com.songoda.epicfurnaces.EpicFurnaces;
 import com.songoda.epicfurnaces.boost.BoostData;
@@ -25,9 +26,6 @@ import org.bukkit.event.inventory.FurnaceSmeltEvent;
 import org.bukkit.inventory.FurnaceInventory;
 import org.bukkit.inventory.InventoryHolder;
 
-import javax.script.ScriptEngine;
-import javax.script.ScriptEngineManager;
-import javax.script.ScriptException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -56,7 +54,6 @@ public class Furnace {
     private final List<Location> radiusOverheat = new ArrayList<>();
     private final List<Location> radiusFuelshare = new ArrayList<>();
     private final List<UUID> accessList = new ArrayList<>();
-    private final Map<String, Integer> cache = new HashMap<>();
 
     public Furnace(Location location) {
         this.location = location;
@@ -244,20 +241,7 @@ public class Furnace {
     public int getPerformanceTotal(Material material) {
         String cap = (material.name().contains("BLAST") || material.name().contains("SMOKER") ? "100" : "200");
         String equation = "(" + level.getPerformance() + " / 100) * " + cap;
-        try {
-            if (!cache.containsKey(equation)) {
-                ScriptEngineManager mgr = new ScriptEngineManager(null);
-                ScriptEngine engine = mgr.getEngineByName("JavaScript");
-                int num = (int) Math.round(Double.parseDouble(engine.eval("(" + level.getPerformance() + " / 100) * " + cap).toString()));
-                cache.put(equation, num);
-                return num;
-            } else {
-                return cache.get(equation);
-            }
-        } catch (ScriptException e) {
-            e.printStackTrace();
-        }
-        return 0;
+        return (int) MathUtils.eval(equation);
     }
 
     public boolean addToAccessList(OfflinePlayer player) {
diff --git a/src/main/java/com/songoda/epicfurnaces/gui/GUIOverview.java b/src/main/java/com/songoda/epicfurnaces/gui/GUIOverview.java
index a3c21da..5109154 100644
--- a/src/main/java/com/songoda/epicfurnaces/gui/GUIOverview.java
+++ b/src/main/java/com/songoda/epicfurnaces/gui/GUIOverview.java
@@ -2,7 +2,6 @@ package com.songoda.epicfurnaces.gui;
 
 import com.songoda.core.compatibility.CompatibleMaterial;
 import com.songoda.core.gui.CustomizableGui;
-import com.songoda.core.gui.Gui;
 import com.songoda.core.gui.GuiUtils;
 import com.songoda.core.input.ChatPrompt;
 import com.songoda.epicfurnaces.EpicFurnaces;
diff --git a/src/main/java/com/songoda/epicfurnaces/gui/GUIRemoteAccess.java b/src/main/java/com/songoda/epicfurnaces/gui/GUIRemoteAccess.java
index 82b5501..53efa9b 100644
--- a/src/main/java/com/songoda/epicfurnaces/gui/GUIRemoteAccess.java
+++ b/src/main/java/com/songoda/epicfurnaces/gui/GUIRemoteAccess.java
@@ -16,7 +16,6 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.inventory.meta.SkullMeta;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;
 import java.util.stream.Collectors;
diff --git a/src/main/java/com/songoda/epicfurnaces/listeners/BlockListeners.java b/src/main/java/com/songoda/epicfurnaces/listeners/BlockListeners.java
index b84e9b4..b2cc32b 100644
--- a/src/main/java/com/songoda/epicfurnaces/listeners/BlockListeners.java
+++ b/src/main/java/com/songoda/epicfurnaces/listeners/BlockListeners.java
@@ -16,6 +16,7 @@ import org.bukkit.event.block.BlockFormEvent;
 import org.bukkit.event.block.BlockPlaceEvent;
 import org.bukkit.inventory.ItemStack;
 
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -46,14 +47,13 @@ public class BlockListeners implements Listener {
                 return;
             }
         }
-
     }
 
     @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
     public void onBlockPlace(BlockPlaceEvent event) {
 
         if (plugin.getBlacklistHandler().isBlacklisted(event.getPlayer().getWorld())
-                || !event.getBlock().getType().name().contains("FURNACE")  && !event.getBlock().getType().name().contains("SMOKER"))
+                || !event.getBlock().getType().name().contains("FURNACE") && !event.getBlock().getType().name().contains("SMOKER"))
             return;
 
         ItemStack item = event.getItemInHand();
@@ -74,7 +74,7 @@ public class BlockListeners implements Listener {
         plugin.getFurnaceManager().addFurnace(furnace);
         plugin.getDataManager().createFurnace(furnace);
 
-        plugin.updateHologram(furnace);
+        plugin.updateHolograms(Collections.singleton(furnace));
     }
 
     @EventHandler(priority = EventPriority.HIGHEST, ignoreCancelled = true)
diff --git a/src/main/java/com/songoda/epicfurnaces/listeners/InventoryListeners.java b/src/main/java/com/songoda/epicfurnaces/listeners/InventoryListeners.java
index e209784..971a767 100644
--- a/src/main/java/com/songoda/epicfurnaces/listeners/InventoryListeners.java
+++ b/src/main/java/com/songoda/epicfurnaces/listeners/InventoryListeners.java
@@ -36,7 +36,6 @@ public class InventoryListeners implements Listener {
             furnace.updateCook();
     }
 
-    @SuppressWarnings("unchecked")
     @EventHandler
     public void onInventoryClick(InventoryClickEvent event) {
         if (event.getSlot() != 64537) {
diff --git a/src/main/java/com/songoda/epicfurnaces/settings/Settings.java b/src/main/java/com/songoda/epicfurnaces/settings/Settings.java
index fd3f41c..712a95b 100644
--- a/src/main/java/com/songoda/epicfurnaces/settings/Settings.java
+++ b/src/main/java/com/songoda/epicfurnaces/settings/Settings.java
@@ -5,11 +5,8 @@ import com.songoda.core.configuration.Config;
 import com.songoda.core.configuration.ConfigSetting;
 import com.songoda.core.hooks.EconomyManager;
 import com.songoda.core.hooks.HologramManager;
-import com.songoda.core.hooks.ProtectionManager;
 import com.songoda.epicfurnaces.EpicFurnaces;
 
-import java.util.stream.Collectors;
-
 public class Settings {
 
     static final Config config = EpicFurnaces.getInstance().getCoreConfig();
@@ -44,8 +41,7 @@ public class Settings {
     public static final ConfigSetting HOLOGRAM_PLUGIN = new ConfigSetting(config, "Main.Hologram",
             HologramManager.getHolograms() == null ? "HolographicDisplays" : HologramManager.getHolograms().getName(),
             "Which hologram plugin should be used?",
-            "You can choose from \"" + HologramManager.getManager().getRegisteredPlugins().stream().collect(Collectors.joining(", ")) + "\".");
-
+            "You can choose from \"" + String.join(", ", HologramManager.getManager().getRegisteredPlugins()) + "\".");
 
     public static final ConfigSetting HOLOGRAMS = new ConfigSetting(config, "Main.Furnaces Have Holograms", true);
 
@@ -68,7 +64,7 @@ public class Settings {
 
     public static final ConfigSetting ECONOMY_PLUGIN = new ConfigSetting(config, "Main.Economy", EconomyManager.getEconomy() == null ? "Vault" : EconomyManager.getEconomy().getName(),
             "Which economy plugin should be used?",
-            "Supported plugins you have installed: \"" + EconomyManager.getManager().getRegisteredPlugins().stream().collect(Collectors.joining("\", \"")) + "\".");
+            "Supported plugins you have installed: \"" + String.join("\", \"", EconomyManager.getManager().getRegisteredPlugins()) + "\".");
 
     public static final ConfigSetting REWARD_ICON = new ConfigSetting(config, "Interfaces.Reward Icon", "GOLDEN_APPLE");
     public static final ConfigSetting PERFORMANCE_ICON = new ConfigSetting(config, "Interfaces.Performance Icon", "REDSTONE");
diff --git a/src/main/java/com/songoda/epicfurnaces/tasks/FurnaceTask.java b/src/main/java/com/songoda/epicfurnaces/tasks/FurnaceTask.java
index 6d9bbdd..7aafc62 100644
--- a/src/main/java/com/songoda/epicfurnaces/tasks/FurnaceTask.java
+++ b/src/main/java/com/songoda/epicfurnaces/tasks/FurnaceTask.java
@@ -19,7 +19,7 @@ public class FurnaceTask extends BukkitRunnable {
     private static FurnaceTask instance;
 
     private final EpicFurnaces plugin;
-    final HashSet<Location> toRemove = new HashSet();
+    final HashSet<Location> toRemove = new HashSet<>();
     boolean doParticles;
 
     private FurnaceTask(EpicFurnaces plugin) {
@@ -56,7 +56,7 @@ public class FurnaceTask extends BukkitRunnable {
                     }
                 });
         if (!toRemove.isEmpty()) {
-            toRemove.stream().forEach(l -> plugin.getFurnaceManager().removeFurnace(l));
+            toRemove.forEach(l -> plugin.getFurnaceManager().removeFurnace(l));
             toRemove.clear();
         }
     }
@@ -81,7 +81,7 @@ public class FurnaceTask extends BukkitRunnable {
             else if (block.getType() == Material.ICE || block.getType() == Material.PACKED_ICE)
                 block.setType(Material.WATER);
             else
-               continue;
+                continue;
 
             if (doParticles) {
                 float xx = (float) (0 + (Math.random() * .75));
diff --git a/src/main/java/com/songoda/epicfurnaces/tasks/HologramTask.java b/src/main/java/com/songoda/epicfurnaces/tasks/HologramTask.java
index 4cd5c85..009d06b 100644
--- a/src/main/java/com/songoda/epicfurnaces/tasks/HologramTask.java
+++ b/src/main/java/com/songoda/epicfurnaces/tasks/HologramTask.java
@@ -2,7 +2,6 @@ package com.songoda.epicfurnaces.tasks;
 
 import com.songoda.core.hooks.HologramManager;
 import com.songoda.epicfurnaces.EpicFurnaces;
-import com.songoda.epicfurnaces.furnace.Furnace;
 import org.bukkit.scheduler.BukkitRunnable;
 
 public class HologramTask extends BukkitRunnable {
@@ -28,8 +27,6 @@ public class HologramTask extends BukkitRunnable {
     public void run() {
         if (!HologramManager.getManager().isEnabled()) return;
 
-        for (Furnace furnace : plugin.getFurnaceManager().getFurnaces().values()) {
-            plugin.updateHologram(furnace);
-        }
+        plugin.updateHolograms(plugin.getFurnaceManager().getFurnaces().values());
     }
 }
\ No newline at end of file
diff --git a/src/main/java/com/songoda/epicfurnaces/utils/Methods.java b/src/main/java/com/songoda/epicfurnaces/utils/Methods.java
index 562065d..89bfd66 100644
--- a/src/main/java/com/songoda/epicfurnaces/utils/Methods.java
+++ b/src/main/java/com/songoda/epicfurnaces/utils/Methods.java
@@ -6,7 +6,6 @@ import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import org.bukkit.Location;
 import org.bukkit.World;
-import org.bukkit.block.Block;
 
 import java.text.DecimalFormat;
 import java.util.Arrays;
@@ -52,7 +51,8 @@ public class Methods {
         str = str.replace(".0", "").replace("/", "");
         return str;
     }
-    private static Map<String, Location> serializeCache = new HashMap<>();
+
+    private static final Map<String, Location> serializeCache = new HashMap<>();
 
     /**
      * Deserializes a location from the string.