diff --git a/src/main/java/server/StatEffect.java b/src/main/java/server/StatEffect.java
index 6c06f47b8d..aa682f2e35 100644
--- a/src/main/java/server/StatEffect.java
+++ b/src/main/java/server/StatEffect.java
@@ -46,7 +46,6 @@ import server.life.Monster;
 import server.maps.*;
 import server.partyquest.CarnivalFactory;
 import server.partyquest.CarnivalFactory.MCSkill;
-import tools.ArrayMap;
 import tools.PacketCreator;
 import tools.Pair;
 
@@ -422,7 +421,7 @@ public class StatEffect {
         ret.itemCon = DataTool.getInt("itemCon", source, 0);
         ret.itemConNo = DataTool.getInt("itemConNo", source, 0);
         ret.moveTo = DataTool.getInt("moveTo", source, -1);
-        Map<MonsterStatus, Integer> monsterStatus = new ArrayMap<>();
+        Map<MonsterStatus, Integer> monsterStatus = new EnumMap<>(MonsterStatus.class);
         if (skill) {
             switch (sourceid) {
                 // BEGINNER
diff --git a/src/main/java/server/life/MobSkill.java b/src/main/java/server/life/MobSkill.java
index 6456611952..0ab6ca91fb 100644
--- a/src/main/java/server/life/MobSkill.java
+++ b/src/main/java/server/life/MobSkill.java
@@ -35,14 +35,11 @@ import server.maps.MapObject;
 import server.maps.MapObjectType;
 import server.maps.MapleMap;
 import server.maps.Mist;
-import tools.ArrayMap;
 import tools.Randomizer;
 
 import java.awt.*;
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 /**
  * @author Danny (Leifde)
@@ -196,7 +193,7 @@ public class MobSkill {
     // TODO: avoid output argument banishPlayersOutput
     public void applyEffect(Character player, Monster monster, boolean skill, List<Character> banishPlayersOutput) {
         Disease disease = null;
-        Map<MonsterStatus, Integer> stats = new ArrayMap<>();
+        Map<MonsterStatus, Integer> stats = new EnumMap<>(MonsterStatus.class);
         List<Integer> reflection = new ArrayList<>();
         switch (type) {
             case ATTACK_UP, ATTACK_UP_M, PAD -> stats.put(MonsterStatus.WEAPON_ATTACK_UP, x);
@@ -419,7 +416,7 @@ public class MobSkill {
     }
 
     public List<Integer> getSummons() {
-        return new ArrayList<>(toSummon);
+        return toSummon;
     }
 
     public int getSpawnEffect() {
diff --git a/src/main/java/tools/ArrayMap.java b/src/main/java/tools/ArrayMap.java
deleted file mode 100644
index 4d5682bcc3..0000000000
--- a/src/main/java/tools/ArrayMap.java
+++ /dev/null
@@ -1,145 +0,0 @@
-/*
-	This file is part of the OdinMS Maple Story Server
-    Copyright (C) 2008 Patrick Huy <patrick.huy@frz.cc>
-		       Matthias Butz <matze@odinms.de>
-		       Jan Christian Meyer <vimes@odinms.de>
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU Affero General Public License as
-    published by the Free Software Foundation version 3 as published by
-    the Free Software Foundation. You may not use, modify or distribute
-    this program under any other version of the GNU Affero General Public
-    License.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU Affero General Public License for more details.
-
-    You should have received a copy of the GNU Affero General Public License
-    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-package tools;
-
-import java.util.*;
-
-// TODO: remove
-public class ArrayMap<K, V> extends AbstractMap<K, V> {
-
-    static class Entry<K, V> implements Map.Entry<K, V> {
-        protected K key;
-        protected V value;
-
-        public Entry(K key, V value) {
-            this.key = key;
-            this.value = value;
-        }
-
-        @Override
-        public K getKey() {
-            return key;
-        }
-
-        @Override
-        public V getValue() {
-            return value;
-        }
-
-        @Override
-        public V setValue(V newValue) {
-            V oldValue = value;
-            value = newValue;
-            return oldValue;
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (o instanceof Map.Entry<?, ?> e) {
-                return (key == null ? e.getKey() == null : key.equals(e.getKey())) && (value == null ? e.getValue() == null : value.equals(e.getValue()));
-            }
-            return false;
-        }
-
-        @Override
-        public int hashCode() {
-            int keyHash = (key == null ? 0 : key.hashCode());
-            int valueHash = (value == null ? 0 : value.hashCode());
-            return keyHash ^ valueHash;
-        }
-
-        @Override
-        public String toString() {
-            return key + "=" + value;
-        }
-    }
-
-    private Set<? extends java.util.Map.Entry<K, V>> entries = null;
-    private final ArrayList<Entry<K, V>> list;
-
-    public ArrayMap() {
-        list = new ArrayList<>();
-    }
-
-    public ArrayMap(Map<K, V> map) {
-        list = new ArrayList<>();
-        putAll(map);
-    }
-
-    public ArrayMap(int initialCapacity) {
-        list = new ArrayList<>(initialCapacity);
-    }
-
-    @Override
-    @SuppressWarnings("unchecked")
-    public Set<java.util.Map.Entry<K, V>> entrySet() {
-        if (entries == null) {
-            entries = new AbstractSet<Entry<K, V>>() {
-                @Override
-                public void clear() {
-                    throw new UnsupportedOperationException();
-                }
-
-                @Override
-                public Iterator<Entry<K, V>> iterator() {
-                    return list.iterator();
-                }
-
-                @Override
-                public int size() {
-                    return list.size();
-                }
-            };
-        }
-        return (Set<java.util.Map.Entry<K, V>>) entries;
-    }
-
-    @Override
-    public V put(K key, V value) {
-        int size = list.size();
-        Entry<K, V> entry = null;
-        int i;
-        if (key == null) {
-            for (i = 0; i < size; i++) {
-                entry = (list.get(i));
-                if (entry.getKey() == null) {
-                    break;
-                }
-            }
-        } else {
-            for (i = 0; i < size; i++) {
-                entry = (list.get(i));
-                if (key.equals(entry.getKey())) {
-                    break;
-                }
-            }
-        }
-        V oldValue = null;
-        if (i < size) {
-            oldValue = entry.getValue();
-            entry.setValue(value);
-        } else {
-            list.add(new Entry<>(key, value));
-        }
-        return oldValue;
-    }
-}