diff --git a/src/main/java/xyz/zhouxy/plusone/commons/collection/ListTools.java b/src/main/java/xyz/zhouxy/plusone/commons/collection/ListTools.java
deleted file mode 100644
index 1ff2972..0000000
--- a/src/main/java/xyz/zhouxy/plusone/commons/collection/ListTools.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package xyz.zhouxy.plusone.commons.collection;
-
-import java.util.List;
-import java.util.function.Function;
-
-public class ListTools {
-
-    public static <T> void transformValue(List<T> list, int index, Function<T, ? extends T> func) {
-        list.set(index, func.apply(list.get(index)));
-    }
-
-    private ListTools() {
-        throw new IllegalStateException("Utility class");
-    }
-}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/collection/MapTools.java b/src/main/java/xyz/zhouxy/plusone/commons/collection/MapTools.java
deleted file mode 100644
index f96dab8..0000000
--- a/src/main/java/xyz/zhouxy/plusone/commons/collection/MapTools.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package xyz.zhouxy.plusone.commons.collection;
-
-import java.util.Map;
-import java.util.function.Function;
-
-public class MapTools {
-
-    public static <K, V> void transformValue(Map<K, V> map, K key, Function<V, ? extends V> func) {
-        if (map.containsKey(key)) {
-            map.put(key, func.apply(map.get(key)));
-        }
-    }
-
-    private MapTools() {
-        throw new IllegalStateException("Utility class");
-    }
-}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/collection/TableTools.java b/src/main/java/xyz/zhouxy/plusone/commons/collection/TableTools.java
deleted file mode 100644
index 0070b05..0000000
--- a/src/main/java/xyz/zhouxy/plusone/commons/collection/TableTools.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package xyz.zhouxy.plusone.commons.collection;
-
-import com.google.common.collect.Table;
-
-public class TableTools {
-
-    public static <R, C, V> Table<R, C, V> synchronizedTable(Table<R, C, V> t) {
-        if (t instanceof SynchronizedTable) {
-            return t;
-        }
-        return SynchronizedTable.of(t);
-    }
-
-    private TableTools() {
-        throw new IllegalStateException("Utility class");
-    }
-}
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
index c5d7bd3..2fd3849 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
@@ -17,23 +17,14 @@
 package xyz.zhouxy.plusone.commons.util;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
-import java.util.TreeMap;
-import java.util.function.Function;
 
 import javax.annotation.Nullable;
 
 import com.google.common.annotations.Beta;
 
-import xyz.zhouxy.plusone.commons.collection.CollectionTools;
-import xyz.zhouxy.plusone.commons.collection.SafeConcurrentHashMap;
-
 @Beta
 public class ArrayTools {
 
@@ -186,61 +177,6 @@ public class ArrayTools {
         return result;
     }
 
-    // array -> map
-
-    public static <K, V> HashMap<K, V> toHashMap(
-            V[] c,
-            Function<? super V, K> keyGenerator,
-            int initialCapacity) {
-        HashMap<K, V> map = new HashMap<>(initialCapacity);
-        fillIntoEmptyMap(map, c, keyGenerator);
-        return map;
-    }
-
-    public static <K, V> HashMap<K, V> toHashMap(
-            V[] c,
-            Function<? super V, K> keyGenerator) {
-        return toHashMap(c, keyGenerator, c.length);
-    }
-
-    public static <K, V> SafeConcurrentHashMap<K, V> toConcurrentHashMap(
-            V[] c,
-            Function<? super V, K> keyGenerator,
-            int initialCapacity) {
-        SafeConcurrentHashMap<K, V> map = new SafeConcurrentHashMap<>(initialCapacity);
-        fillIntoEmptyMap(map, c, keyGenerator);
-        return map;
-    }
-
-    public static <K, V> SafeConcurrentHashMap<K, V> toConcurrentHashMap(
-            V[] c,
-            Function<? super V, K> keyGenerator) {
-        return toConcurrentHashMap(c, keyGenerator, c.length);
-    }
-
-    public static <K extends Comparable<? super K>, V> TreeMap<K, V> toTreeMap(
-            V[] c,
-            Function<? super V, K> keyGenerator) {
-        TreeMap<K, V> map = new TreeMap<>();
-        fillIntoEmptyMap(map, c, keyGenerator);
-        return map;
-    }
-
-    public static <K, V> TreeMap<K, V> toTreeMap(
-            V[] c,
-            Function<? super V, K> keyGenerator,
-            Comparator<? super K> keyComparator) {
-        TreeMap<K, V> map = new TreeMap<>(keyComparator);
-        fillIntoEmptyMap(map, c, keyGenerator);
-        return map;
-    }
-
-    public static <K, V> void fillIntoEmptyMap(
-            Map<K, ? super V> map, V[] c,
-            Function<? super V, K> keyGenerator) {
-        CollectionTools.fillIntoEmptyMap(map, Arrays.asList(c), keyGenerator);
-    }
-
     private ArrayTools() {
         throw new IllegalStateException("Utility class");
     }