diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TAbstractMap.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TAbstractMap.java
index 8e422840c..c56985038 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TAbstractMap.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TAbstractMap.java
@@ -128,8 +128,8 @@ public abstract class TAbstractMap<K, V> extends TObject implements TMap<K, V> {
         }
     }
 
-    private KeySet cachedKeySet;
-    private Values cachedValues;
+    TSet<K> cachedKeySet;
+    TCollection<V> cachedValues;
 
     protected TAbstractMap() {
     }
diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TCollections.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TCollections.java
index ef02b031c..308115072 100644
--- a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TCollections.java
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TCollections.java
@@ -93,6 +93,46 @@ public class TCollections extends TObject {
         };
     }
 
+    public static <T> TSet<T> singleton(final T o) {
+        return new TAbstractSet<T>() {
+            @Override public int size() {
+                return 1;
+            }
+            @Override public TIterator<T> iterator() {
+                return new TIterator<T>() {
+                    private boolean read;
+                    @Override public boolean hasNext() {
+                        return !read;
+                    }
+                    @Override public T next() {
+                        if (read) {
+                            throw new TNoSuchElementException();
+                        }
+                        read = true;
+                        return o;
+                    }
+                    @Override public void remove() {
+                        throw new TUnsupportedOperationException();
+                    }
+                };
+            }
+            @Override public boolean contains(Object o2) {
+                return TObjects.equals(o, o2);
+            }
+        };
+    }
+
+    public static <T> TList<T> unmodifiableList(final TList<? extends T> list) {
+        return new TAbstractList<T>() {
+            @Override public T get(int index) {
+                return list.get(index);
+            }
+            @Override public int size() {
+                return list.size();
+            }
+        };
+    }
+
     public static <T> TList<T> nCopies(final int n, final T o) {
         return new TAbstractList<T>() {
             @Override public T get(int index) {
diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/THashMap.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/THashMap.java
new file mode 100644
index 000000000..0346163ea
--- /dev/null
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/THashMap.java
@@ -0,0 +1,602 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.teavm.classlib.java.util;
+
+import java.util.*;
+import org.teavm.classlib.java.io.TSerializable;
+import org.teavm.classlib.java.lang.TCloneNotSupportedException;
+import org.teavm.classlib.java.lang.TIllegalArgumentException;
+import org.teavm.classlib.java.lang.TIllegalStateException;
+import org.teavm.classlib.java.lang.TObject;
+
+public class THashMap<K, V> extends TAbstractMap<K, V> implements TSerializable {
+    transient int elementCount;
+    transient Entry<K, V>[] elementData;
+    transient int modCount = 0;
+    private static final int DEFAULT_SIZE = 16;
+    final float loadFactor;
+    int threshold;
+
+    static class Entry<K, V> extends TMapEntry<K, V> {
+        final int origKeyHash;
+
+        Entry<K, V> next;
+
+        Entry(K theKey, int hash) {
+            super(theKey, null);
+            this.origKeyHash = hash;
+        }
+
+        Entry(K theKey, V theValue) {
+            super(theKey, theValue);
+            origKeyHash = (theKey == null ? 0 : computeHashCode(theKey));
+        }
+
+        @Override
+        @SuppressWarnings("unchecked")
+        public Object clone() {
+            Entry<K, V> entry = (Entry<K, V>) super.clone();
+            if (next != null) {
+                entry.next = (Entry<K, V>) next.clone();
+            }
+            return entry;
+        }
+    }
+
+    private static class AbstractMapIterator<K, V>  {
+        private int position = 0;
+        int expectedModCount;
+        Entry<K, V> futureEntry;
+        Entry<K, V> currentEntry;
+        Entry<K, V> prevEntry;
+
+        final THashMap<K, V> associatedMap;
+
+        AbstractMapIterator(THashMap<K, V> hm) {
+            associatedMap = hm;
+            expectedModCount = hm.modCount;
+            futureEntry = null;
+        }
+
+        public boolean hasNext() {
+            if (futureEntry != null) {
+                return true;
+            }
+            while (position < associatedMap.elementData.length) {
+                if (associatedMap.elementData[position] == null) {
+                    position++;
+                } else {
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        final void checkConcurrentMod() throws ConcurrentModificationException {
+            if (expectedModCount != associatedMap.modCount) {
+                throw new TConcurrentModificationException();
+            }
+        }
+
+        final void makeNext() {
+            checkConcurrentMod();
+            if (!hasNext()) {
+                throw new TNoSuchElementException();
+            }
+            if (futureEntry == null) {
+                currentEntry = associatedMap.elementData[position++];
+                futureEntry = currentEntry.next;
+                prevEntry = null;
+            } else {
+                if(currentEntry!=null){
+                    prevEntry = currentEntry;
+                }
+                currentEntry = futureEntry;
+                futureEntry = futureEntry.next;
+            }
+        }
+
+        public final void remove() {
+            checkConcurrentMod();
+            if (currentEntry == null) {
+                throw new TIllegalStateException();
+            }
+            if(prevEntry == null){
+                int index = currentEntry.origKeyHash & (associatedMap.elementData.length - 1);
+                associatedMap.elementData[index] = associatedMap.elementData[index].next;
+            } else {
+                prevEntry.next = currentEntry.next;
+            }
+            currentEntry = null;
+            expectedModCount++;
+            associatedMap.modCount++;
+            associatedMap.elementCount--;
+
+        }
+    }
+
+
+    private static class EntryIterator <K, V> extends AbstractMapIterator<K, V>
+            implements TIterator<TMap.Entry<K, V>> {
+        EntryIterator (THashMap<K, V> map) {
+            super(map);
+        }
+
+        @Override
+        public TMap.Entry<K, V> next() {
+            makeNext();
+            return currentEntry;
+        }
+    }
+
+    private static class KeyIterator <K, V> extends AbstractMapIterator<K, V> implements TIterator<K> {
+        KeyIterator (THashMap<K, V> map) {
+            super(map);
+        }
+
+        @Override
+        public K next() {
+            makeNext();
+            return currentEntry.key;
+        }
+    }
+
+    private static class ValueIterator <K, V> extends AbstractMapIterator<K, V> implements TIterator<V> {
+        ValueIterator (THashMap<K, V> map) {
+            super(map);
+        }
+
+        @Override
+        public V next() {
+            makeNext();
+            return currentEntry.value;
+        }
+    }
+
+    static class HashMapEntrySet<KT, VT> extends TAbstractSet<TMap.Entry<KT, VT>> {
+        private final THashMap<KT, VT> associatedMap;
+
+        public HashMapEntrySet(THashMap<KT, VT> hm) {
+            associatedMap = hm;
+        }
+
+        THashMap<KT, VT> hashMap() {
+            return associatedMap;
+        }
+
+        @Override
+        public int size() {
+            return associatedMap.elementCount;
+        }
+
+        @Override
+        public void clear() {
+            associatedMap.clear();
+        }
+
+        @Override
+        public boolean remove(Object object) {
+            if (object instanceof TMap.Entry) {
+                TMap.Entry<?, ?> oEntry = (TMap.Entry<?, ?>) object;
+                TMap.Entry<KT,VT> entry = associatedMap.getEntry(oEntry.getKey());
+                if(valuesEq(entry, oEntry)) {
+                    associatedMap.removeEntry(entry);
+                    return true;
+                }
+            }
+            return false;
+        }
+
+        @Override
+        public boolean contains(Object object) {
+            if (object instanceof TMap.Entry) {
+                TMap.Entry<?, ?> oEntry = (TMap.Entry<?, ?>) object;
+                TMap.Entry<KT, VT> entry = associatedMap.getEntry(oEntry.getKey());
+                return valuesEq(entry, oEntry);
+            }
+            return false;
+        }
+
+        private static boolean valuesEq(TMap.Entry<?, ?> entry, TMap.Entry<?, ?> oEntry) {
+            return (entry != null) &&
+                                   ((entry.getValue() == null) ?
+                                    (oEntry.getValue() == null) :
+                                    (areEqualValues(entry.getValue(), oEntry.getValue())));
+        }
+
+        @Override
+        public TIterator<TMap.Entry<KT, VT>> iterator() {
+            return new EntryIterator<>(associatedMap);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    Entry<K, V>[] newElementArray(int s) {
+        return new Entry[s];
+    }
+
+    public THashMap() {
+        this(DEFAULT_SIZE);
+    }
+
+    public THashMap(int capacity) {
+        this(capacity, 0.75f);  // default load factor of 0.75
+    }
+
+    private static final int calculateCapacity(int x) {
+        if(x >= 1 << 30){
+            return 1 << 30;
+        }
+        if(x == 0){
+            return 16;
+        }
+        x = x -1;
+        x |= x >> 1;
+        x |= x >> 2;
+        x |= x >> 4;
+        x |= x >> 8;
+        x |= x >> 16;
+        return x + 1;
+    }
+
+    /**
+     * Constructs a new {@code HashMap} instance with the specified capacity and
+     * load factor.
+     *
+     * @param capacity
+     *            the initial capacity of this hash map.
+     * @param loadFactor
+     *            the initial load factor.
+     * @throws IllegalArgumentException
+     *                when the capacity is less than zero or the load factor is
+     *                less or equal to zero.
+     */
+    public THashMap(int capacity, float loadFactor) {
+        if (capacity >= 0 && loadFactor > 0) {
+            capacity = calculateCapacity(capacity);
+            elementCount = 0;
+            elementData = newElementArray(capacity);
+            this.loadFactor = loadFactor;
+            computeThreshold();
+        } else {
+            throw new TIllegalArgumentException();
+        }
+    }
+
+    public THashMap(TMap<? extends K, ? extends V> map) {
+        this(calculateCapacity(map.size()));
+        putAllImpl(map);
+    }
+
+    @Override
+    public void clear() {
+        if (elementCount > 0) {
+            elementCount = 0;
+            Arrays.fill(elementData, null);
+            modCount++;
+        }
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public TObject clone() {
+        try {
+            THashMap<K, V> map = (THashMap<K, V>) super.clone();
+            map.elementCount = 0;
+            map.elementData = newElementArray(elementData.length);
+            map.putAll(this);
+
+            return map;
+        } catch (TCloneNotSupportedException e) {
+            return null;
+        }
+    }
+
+    private void computeThreshold() {
+        threshold = (int) (elementData.length * loadFactor);
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        Entry<K, V> m = getEntry(key);
+        return m != null;
+    }
+
+    @Override
+    public boolean containsValue(Object value) {
+        if (value != null) {
+            for (int i = 0; i < elementData.length; i++) {
+                Entry<K, V> entry = elementData[i];
+                while (entry != null) {
+                    if (areEqualValues(value, entry.value)) {
+                        return true;
+                    }
+                    entry = entry.next;
+                }
+            }
+        } else {
+            for (int i = 0; i < elementData.length; i++) {
+                Entry<K, V> entry = elementData[i];
+                while (entry != null) {
+                    if (entry.value == null) {
+                        return true;
+                    }
+                    entry = entry.next;
+                }
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public TSet<TMap.Entry<K, V>> entrySet() {
+        return new HashMapEntrySet<>(this);
+    }
+
+    @Override
+    public V get(Object key) {
+        Entry<K, V> m = getEntry(key);
+        if (m != null) {
+            return m.value;
+        }
+        return null;
+    }
+
+    final Entry<K, V> getEntry(Object key) {
+        Entry<K, V> m;
+        if (key == null) {
+            m = findNullKeyEntry();
+        } else {
+            int hash = computeHashCode(key);
+            int index = hash & (elementData.length - 1);
+            m = findNonNullKeyEntry(key, index, hash);
+        }
+        return m;
+    }
+
+    final Entry<K,V> findNonNullKeyEntry(Object key, int index, int keyHash) {
+        Entry<K,V> m = elementData[index];
+        while (m != null
+                && (m.origKeyHash != keyHash || !areEqualKeys(key, m.key))) {
+            m = m.next;
+        }
+        return m;
+    }
+
+    final Entry<K,V> findNullKeyEntry() {
+        Entry<K,V> m = elementData[0];
+        while (m != null && m.key != null)
+            m = m.next;
+        return m;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return elementCount == 0;
+    }
+
+    @Override
+    public TSet<K> keySet() {
+        if (cachedKeySet == null) {
+            cachedKeySet = new TAbstractSet<K>() {
+                @Override public boolean contains(Object object) {
+                    return containsKey(object);
+                }
+                @Override public int size() {
+                    return THashMap.this.size();
+                }
+                @Override public void clear() {
+                    THashMap.this.clear();
+                }
+                @Override public boolean remove(Object key) {
+                    Entry<K, V> entry = THashMap.this.removeEntry(key);
+                    return entry != null;
+                }
+                @Override public TIterator<K> iterator() {
+                    return new KeyIterator<>(THashMap.this);
+                }
+            };
+        }
+        return cachedKeySet;
+    }
+
+    @Override
+    public V put(K key, V value) {
+        return putImpl(key, value);
+    }
+
+    V putImpl(K key, V value) {
+        Entry<K,V> entry;
+        if(key == null) {
+            entry = findNullKeyEntry();
+            if (entry == null) {
+                modCount++;
+                entry = createHashedEntry(null, 0, 0);
+                if (++elementCount > threshold) {
+                    rehash();
+                }
+            }
+        } else {
+            int hash = computeHashCode(key);
+            int index = hash & (elementData.length - 1);
+            entry = findNonNullKeyEntry(key, index, hash);
+            if (entry == null) {
+                modCount++;
+                entry = createHashedEntry(key, index, hash);
+                if (++elementCount > threshold) {
+                    rehash();
+                }
+            }
+        }
+
+        V result = entry.value;
+        entry.value = value;
+        return result;
+    }
+
+    Entry<K, V> createEntry(K key, int index, V value) {
+        Entry<K, V> entry = new Entry<>(key, value);
+        entry.next = elementData[index];
+        elementData[index] = entry;
+        return entry;
+    }
+
+    Entry<K,V> createHashedEntry(K key, int index, int hash) {
+        Entry<K,V> entry = new Entry<>(key,hash);
+        entry.next = elementData[index];
+        elementData[index] = entry;
+        return entry;
+    }
+
+    @Override
+    public void putAll(TMap<? extends K, ? extends V> map) {
+        if (!map.isEmpty()) {
+            putAllImpl(map);
+        }
+    }
+
+    private void putAllImpl(TMap<? extends K, ? extends V> map) {
+        int capacity = elementCount + map.size();
+        if (capacity > threshold) {
+            rehash(capacity);
+        }
+        for (TIterator<? extends TMap.Entry<? extends K, ? extends V>> iter = map.entrySet().iterator();
+                iter.hasNext();) {
+            TMap.Entry<? extends K, ? extends V> entry = iter.next();
+            putImpl(entry.getKey(), entry.getValue());
+        }
+    }
+
+    void rehash(int capacity) {
+        int length = calculateCapacity((capacity == 0 ? 1 : capacity << 1));
+
+        Entry<K, V>[] newData = newElementArray(length);
+        for (int i = 0; i < elementData.length; i++) {
+            Entry<K, V> entry = elementData[i];
+            elementData[i] = null;
+            while (entry != null) {
+                int index = entry.origKeyHash & (length - 1);
+                Entry<K, V> next = entry.next;
+                entry.next = newData[index];
+                newData[index] = entry;
+                entry = next;
+            }
+        }
+        elementData = newData;
+        computeThreshold();
+    }
+
+    void rehash() {
+        rehash(elementData.length);
+    }
+
+    @Override
+    public V remove(Object key) {
+        Entry<K, V> entry = removeEntry(key);
+        if (entry != null) {
+            return entry.value;
+        }
+        return null;
+    }
+
+    final void removeEntry(Entry<K, V> entry) {
+        int index = entry.origKeyHash & (elementData.length - 1);
+        Entry<K, V> m = elementData[index];
+        if (m == entry) {
+            elementData[index] = entry.next;
+        } else {
+            while (m.next != entry) {
+                m = m.next;
+            }
+            m.next = entry.next;
+
+        }
+        modCount++;
+        elementCount--;
+    }
+
+    final Entry<K, V> removeEntry(Object key) {
+        int index = 0;
+        Entry<K, V> entry;
+        Entry<K, V> last = null;
+        if (key != null) {
+            int hash = computeHashCode(key);
+            index = hash & (elementData.length - 1);
+            entry = elementData[index];
+            while (entry != null && !(entry.origKeyHash == hash && areEqualKeys(key, entry.key))) {
+                last = entry;
+                entry = entry.next;
+            }
+        } else {
+            entry = elementData[0];
+            while (entry != null && entry.key != null) {
+                last = entry;
+                entry = entry.next;
+            }
+        }
+        if (entry == null) {
+            return null;
+        }
+        if (last == null) {
+            elementData[index] = entry.next;
+        } else {
+            last.next = entry.next;
+        }
+        modCount++;
+        elementCount--;
+        return entry;
+    }
+
+    @Override
+    public int size() {
+        return elementCount;
+    }
+
+    @Override
+    public TCollection<V> values() {
+        if (cachedValues == null) {
+            cachedValues = new TAbstractCollection<V>() {
+                @Override public boolean contains(Object object) {
+                    return containsValue(object);
+                }
+                @Override public int size() {
+                    return THashMap.this.size();
+                }
+                @Override public void clear() {
+                    THashMap.this.clear();
+                }
+                @Override public TIterator<V> iterator() {
+                    return new ValueIterator<>(THashMap.this);
+                }
+            };
+        }
+        return cachedValues;
+    }
+
+    static int computeHashCode(Object key) {
+        return key.hashCode();
+    }
+
+    static boolean areEqualKeys(Object key1, Object key2) {
+        return (key1 == key2) || key1.equals(key2);
+    }
+
+    static boolean areEqualValues(Object value1, Object value2) {
+        return (value1 == value2) || value1.equals(value2);
+    }
+}
diff --git a/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TMapEntry.java b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TMapEntry.java
new file mode 100644
index 000000000..2e2c03dd4
--- /dev/null
+++ b/teavm-classlib/src/main/java/org/teavm/classlib/java/util/TMapEntry.java
@@ -0,0 +1,105 @@
+/*
+ *  Copyright 2014 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one or more
+ *  contributor license agreements.  See the NOTICE file distributed with
+ *  this work for additional information regarding copyright ownership.
+ *  The ASF licenses this file to You under the Apache License, Version 2.0
+ *  (the "License"); you may not use this file except in compliance with
+ *  the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.classlib.java.util;
+
+/**
+ * MapEntry is an internal class which provides an implementation of Map.Entry.
+ */
+class TMapEntry<K, V> implements TMap.Entry<K, V>, Cloneable {
+
+    K key;
+    V value;
+
+    interface Type<RT, KT, VT> {
+        RT get(TMapEntry<KT, VT> entry);
+    }
+
+    TMapEntry(K theKey) {
+        key = theKey;
+    }
+
+    TMapEntry(K theKey, V theValue) {
+        key = theKey;
+        value = theValue;
+    }
+
+    @Override
+    public Object clone() {
+        try {
+            return super.clone();
+        } catch (CloneNotSupportedException e) {
+            return null;
+        }
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object) {
+            return true;
+        }
+        if (object instanceof TMap.Entry) {
+            TMap.Entry<?, ?> entry = (TMap.Entry<?, ?>) object;
+            return (key == null ? entry.getKey() == null : key.equals(entry.getKey()))
+                    && (value == null ? entry.getValue() == null : value
+                            .equals(entry.getValue()));
+        }
+        return false;
+    }
+
+    @Override
+    public K getKey() {
+        return key;
+    }
+
+    @Override
+    public V getValue() {
+        return value;
+    }
+
+    @Override
+    public int hashCode() {
+        return (key == null ? 0 : key.hashCode())
+                ^ (value == null ? 0 : value.hashCode());
+    }
+
+    @Override
+    public V setValue(V object) {
+        V result = value;
+        value = object;
+        return result;
+    }
+
+    @Override
+    public String toString() {
+        return key + "=" + value;
+    }
+}