diff --git a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
index bdd69eb418d..e90053fd8ae 100644
--- a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
+++ b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableCollection.kt
@@ -10,7 +10,7 @@ package kotlin.collections
  *
  * @param E the type of elements contained in the collection. The collection is invariant on its element type.
  */
-public abstract class AbstractMutableCollection<E> protected constructor(): MutableCollection<E>, AbstractCollection<E>() {
+public actual abstract class AbstractMutableCollection<E> protected actual constructor(): MutableCollection<E>, AbstractCollection<E>() {
 
     // Bulk Modification Operations
     /**
@@ -18,7 +18,7 @@ public abstract class AbstractMutableCollection<E> protected constructor(): Muta
      *
      * @return `true` if any of the specified elements was added to the collection, `false` if the collection was not modified.
      */
-    override public fun addAll(elements: Collection<E>): Boolean {
+    actual override public fun addAll(elements: Collection<E>): Boolean {
         var changed = false
         for (v in elements) {
             if (add(v)) changed = true
@@ -32,7 +32,7 @@ public abstract class AbstractMutableCollection<E> protected constructor(): Muta
      *
      * @return `true` if the element has been successfully removed; `false` if it was not present in the collection.
      */
-    override fun remove(element: E): Boolean {
+    actual override fun remove(element: E): Boolean {
         val it = iterator()
         while (it.hasNext()) {
             if (it.next() == element) {
@@ -48,19 +48,19 @@ public abstract class AbstractMutableCollection<E> protected constructor(): Muta
      *
      * @return `true` if any of the specified elements was removed from the collection, `false` if the collection was not modified.
      */
-    override public fun removeAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it in elements }
+    actual override public fun removeAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).removeAll { it in elements }
 
     /**
      * Retains only the elements in this collection that are contained in the specified collection.
      *
      * @return `true` if any element was removed from the collection, `false` if the collection was not modified.
      */
-    override public fun retainAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).retainAll { it in elements }
+    actual override public fun retainAll(elements: Collection<E>): Boolean = (this as MutableIterable<E>).retainAll { it in elements }
 
     /**
      * Removes all elements from this collection.
      */
-    override fun clear(): Unit {
+    actual override fun clear(): Unit {
         val it = iterator()
         while (it.hasNext()) {
             it.next()
diff --git a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableMap.kt b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableMap.kt
new file mode 100644
index 00000000000..8dc29978e54
--- /dev/null
+++ b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableMap.kt
@@ -0,0 +1,135 @@
+package kotlin.collections
+
+/**
+ * Provides a skeletal implementation of the [MutableMap] interface.
+ *
+ * The implementor is required to implement [entries] property, which should return mutable set of map entries, and [put] function.
+ *
+ * @param K the type of map keys. The map is invariant on its key type.
+ * @param V the type of map values. The map is invariant on its value type.
+ */
+@SinceKotlin("1.1")
+public actual abstract class AbstractMutableMap<K, V> protected actual constructor() : AbstractMap<K, V>(), MutableMap<K, V> {
+    /**
+     * Associates the specified [value] with the specified [key] in the map.
+     *
+     * @return the previous value associated with the key, or `null` if the key was not present in the map.
+     */
+    actual abstract override fun put(key: K, value: V): V?
+
+
+    /**
+     * A mutable [Map.Entry] shared by several [Map] implementations.
+     */
+    internal open class SimpleEntry<K, V>(override val key: K, value: V) : MutableMap.MutableEntry<K, V> {
+        constructor(entry: Map.Entry<K, V>) : this(entry.key, entry.value)
+
+        private var _value = value
+
+        override val value: V get() = _value
+
+        override fun setValue(newValue: V): V {
+            val oldValue = this._value
+            this._value = newValue
+            return oldValue
+        }
+
+        override fun hashCode(): Int = entryHashCode(this)
+        override fun toString(): String = entryToString(this)
+        override fun equals(other: Any?): Boolean = entryEquals(this, other)
+    }
+
+
+    actual override fun putAll(from: Map<out K, V>) {
+        for ((key, value) in from) {
+            put(key, value)
+        }
+    }
+
+    actual override fun remove(key: K): V? {
+        val iter = entries.iterator()
+        while (iter.hasNext()) {
+            val entry = iter.next()
+            val k = entry.key
+            if (key == k) {
+                val value = entry.value
+                iter.remove()
+                return value
+            }
+        }
+        return null
+    }
+
+    actual override fun clear() {
+        entries.clear()
+    }
+
+    private var _keys: MutableSet<K>? = null
+    actual override val keys: MutableSet<K>
+        get() {
+            if (_keys == null) {
+                _keys = object : AbstractMutableSet<K>() {
+                    override fun add(element: K): Boolean = throw UnsupportedOperationException("Add is not supported on keys")
+                    override fun clear() {
+                        this@AbstractMutableMap.clear()
+                    }
+
+                    override operator fun contains(element: K): Boolean = containsKey(element)
+
+                    override operator fun iterator(): MutableIterator<K> {
+                        val entryIterator = entries.iterator()
+                        return object : MutableIterator<K> {
+                            override fun hasNext(): Boolean = entryIterator.hasNext()
+                            override fun next(): K = entryIterator.next().key
+                            override fun remove() = entryIterator.remove()
+                        }
+                    }
+
+                    override fun remove(element: K): Boolean {
+                        if (containsKey(element)) {
+                            this@AbstractMutableMap.remove(element)
+                            return true
+                        }
+                        return false
+                    }
+
+                    override val size: Int get() = this@AbstractMutableMap.size
+                }
+            }
+            return _keys!!
+        }
+
+    private var _values: MutableCollection<V>? = null
+    actual override val values: MutableCollection<V>
+        get() {
+            if (_values == null) {
+                _values = object : AbstractMutableCollection<V>() {
+                    override fun add(element: V): Boolean = throw UnsupportedOperationException("Add is not supported on values")
+                    override fun clear() = this@AbstractMutableMap.clear()
+
+                    override operator fun contains(element: V): Boolean = containsValue(element)
+
+                    override operator fun iterator(): MutableIterator<V> {
+                        val entryIterator = entries.iterator()
+                        return object : MutableIterator<V> {
+                            override fun hasNext(): Boolean = entryIterator.hasNext()
+                            override fun next(): V = entryIterator.next().value
+                            override fun remove() = entryIterator.remove()
+                        }
+                    }
+
+                    override val size: Int get() = this@AbstractMutableMap.size
+
+                    // TODO: should we implement them this way? Currently it's unspecified in JVM
+                    override fun equals(other: Any?): Boolean {
+                        if (this === other) return true
+                        if (other !is Collection<*>) return false
+                        return AbstractList.orderedEquals(this, other)
+                    }
+
+                    override fun hashCode(): Int = AbstractList.orderedHashCode(this)
+                }
+            }
+            return _values!!
+        }
+}
diff --git a/runtime/src/main/kotlin/kotlin/collections/AbstractMutableSet.kt b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableSet.kt
new file mode 100644
index 00000000000..fedb8e5f55d
--- /dev/null
+++ b/runtime/src/main/kotlin/kotlin/collections/AbstractMutableSet.kt
@@ -0,0 +1,32 @@
+package kotlin.collections
+
+/**
+ * Provides a skeletal implementation of the [MutableSet] interface.
+ *
+ * @param E the type of elements contained in the set. The set is invariant on its element type.
+ */
+@SinceKotlin("1.1")
+public actual abstract class AbstractMutableSet<E> protected actual constructor() : AbstractMutableCollection<E>(), MutableSet<E> {
+    /**
+     * Adds the specified element to the set.
+     *
+     * @return `true` if the element has been added, `false` if the element is already contained in the set.
+     */
+    actual abstract override fun add(element: E): Boolean
+
+    /**
+     * Compares this set with another set instance with the unordered structural equality.
+     *
+     * @return true, if [other] instance is a [Set] of the same size, all elements of which are contained in this set.
+     */
+    override fun equals(other: Any?): Boolean {
+        if (other === this) return true
+        if (other !is Set<*>) return false
+        return AbstractSet.setEquals(this, other)
+    }
+
+    /**
+     * Returns the hash code value for this set.
+     */
+    override fun hashCode(): Int = AbstractSet.unorderedHashCode(this)
+}
\ No newline at end of file
diff --git a/runtime/src/main/kotlin/kotlin/collections/MutableCollections.kt b/runtime/src/main/kotlin/kotlin/collections/MutableCollections.kt
index c9a599ba7b3..ee0e8f75ab2 100644
--- a/runtime/src/main/kotlin/kotlin/collections/MutableCollections.kt
+++ b/runtime/src/main/kotlin/kotlin/collections/MutableCollections.kt
@@ -25,51 +25,3 @@ public actual fun <T> MutableList<T>.sortWith(comparator: Comparator<in T>): Uni
         }
     }
 }
-/**
- * Provides a skeletal implementation of the [MutableMap] interface.
- *
- * The implementor is required to implement [entries] property, which should return mutable set of map entries, and [put] function.
- *
- * @param K the type of map keys. The map is invariant on its key type.
- * @param V the type of map values. The map is invariant on its value type.
- */
-@SinceKotlin("1.1")
-actual abstract class AbstractMutableMap<K, V> protected actual constructor() : AbstractMap<K, V>(), MutableMap<K, V> {
-    /**
-     * Associates the specified [value] with the specified [key] in the map.
-     *
-     * This method is redeclared as abstract, because it's not implemented in the base class,
-     * so it must be always overridden in the concrete mutable collection implementation.
-     *
-     * @return the previous value associated with the key, or `null` if the key was not present in the map.
-     */
-    actual abstract override fun put(key: K, value: V): V?
-
-    /**
-     * Returns a [MutableSet] of all keys in this map.
-     */
-    abstract override val keys: MutableSet<K>
-
-    /**
-     * Returns a [MutableCollection] of all values in this map. Note that this collection may contain duplicate values.
-     */
-    abstract override val values: MutableCollection<V>
-}
-
-/**
- * Provides a skeletal implementation of the [MutableSet] interface.
- *
- * @param E the type of elements contained in the set. The set is invariant on its element type.
- */
-@SinceKotlin("1.1")
-actual abstract class AbstractMutableSet<E> protected actual constructor() : AbstractSet<E>(), MutableSet<E> {
-    /**
-     * Adds the specified element to the set.
-     *
-     * This method is redeclared as abstract, because it's not implemented in the base class,
-     * so it must be always overridden in the concrete mutable collection implementation.
-     *
-     * @return `true` if the element has been added, `false` if the element is already contained in the set.
-     */
-    actual abstract override fun add(element: E): Boolean
-}
\ No newline at end of file