diff --git a/jslib/src/core/javautil.kt b/jslib/src/core/javautil.kt
index 2acaad22beb..4e9a1a3428a 100644
--- a/jslib/src/core/javautil.kt
+++ b/jslib/src/core/javautil.kt
@@ -2,16 +2,13 @@ package java.util
 
 import js.annotations.*;
 
-//LibraryClass
-//public trait Comparator<T> {
-//    fun compare(obj1 : T, obj2 : T) : Int;
-//}
-//
-//LibraryFun("comparator")
-//public fun comparator<T>(f : (T, T) -> Int) : Comparator<T> {}
-//
-//LibraryFun("max")
-//public fun max<T>(col : Collection<T>, comp : Comparator<T>) {}
+LibraryClass
+public trait Comparator<T> {
+    fun compare(obj1 : T, obj2 : T) : Int;
+}
+
+LibraryFun("comparator")
+public fun comparator<T>(f : (T, T) -> Int) : Comparator<T> {}
 
 
 LibraryClass
diff --git a/jslib/src/core/javautilcollections.kt b/jslib/src/core/javautilcollections.kt
new file mode 100644
index 00000000000..22e5d282453
--- /dev/null
+++ b/jslib/src/core/javautilcollections.kt
@@ -0,0 +1,8 @@
+package java.util.Collections;
+
+import js.annotations.LibraryFun
+import java.util.Collection
+import java.util.Comparator
+
+LibraryFun("collectionsMax")
+public fun max<T>(col : Collection<T>, comp : Comparator<T>) {}
\ No newline at end of file
diff --git a/translator/src/org/jetbrains/k2js/config/Config.java b/translator/src/org/jetbrains/k2js/config/Config.java
index 8234d17b646..3741f587396 100644
--- a/translator/src/org/jetbrains/k2js/config/Config.java
+++ b/translator/src/org/jetbrains/k2js/config/Config.java
@@ -31,7 +31,8 @@ public abstract class Config {
             PATH_TO_JS_LIB_SRC + "\\core\\core.kt",
             PATH_TO_JS_LIB_SRC + "\\raphael\\raphael.kt",
             PATH_TO_JS_LIB_SRC + "\\core\\json.kt",
-            PATH_TO_JS_LIB_SRC + "\\html5\\core.kt"
+            PATH_TO_JS_LIB_SRC + "\\html5\\core.kt",
+            PATH_TO_JS_LIB_SRC + "\\core\\javautilcollections.kt"
     );
 
 
diff --git a/translator/test/org/jetbrains/k2js/test/ExtensionPropertyTest.java b/translator/test/org/jetbrains/k2js/test/ExtensionPropertyTest.java
index 510a1830f63..f6b0490f74b 100644
--- a/translator/test/org/jetbrains/k2js/test/ExtensionPropertyTest.java
+++ b/translator/test/org/jetbrains/k2js/test/ExtensionPropertyTest.java
@@ -18,9 +18,13 @@ public final class ExtensionPropertyTest extends TranslationTest {
         testFooBoxIsTrue("simplePropertyWithGetter.kt");
     }
 
-
     @Test
     public void propertyWithGetterAndSetter() throws Exception {
         testFooBoxIsTrue("propertyWithGetterAndSetter.kt");
     }
+
+    @Test
+    public void absExtension() throws Exception {
+        testFooBoxIsTrue("absExtension.kt");
+    }
 }
diff --git a/translator/test/org/jetbrains/k2js/test/WebDemoExamples2Test.java b/translator/test/org/jetbrains/k2js/test/WebDemoExamples2Test.java
index c4b46d4dce3..cc14a7f1229 100644
--- a/translator/test/org/jetbrains/k2js/test/WebDemoExamples2Test.java
+++ b/translator/test/org/jetbrains/k2js/test/WebDemoExamples2Test.java
@@ -32,7 +32,7 @@ public final class WebDemoExamples2Test extends TranslationTest {
         testWithMain("builder", "1", "over9000");
     }
 
-    //TODO: comparator dependencies
+    //TODO: comparator LinkedList dependencies
 //    @Test
 //    public void maze() throws Exception {
 //        testWithMain("maze", "");
diff --git a/translator/testFiles/extensionProperty/cases/absExtension.kt b/translator/testFiles/extensionProperty/cases/absExtension.kt
new file mode 100644
index 00000000000..d0399758498
--- /dev/null
+++ b/translator/testFiles/extensionProperty/cases/absExtension.kt
@@ -0,0 +1,11 @@
+package foo;
+
+val Double.abs : Double
+    get() = if (this > 0) this else -this
+
+fun box() : Boolean {
+    if (4.0.abs != 4.0) return false;
+    if ((-5.2).abs != 5.2) return false;
+
+    return true;
+}
diff --git a/translator/testFiles/kotlin_lib.js b/translator/testFiles/kotlin_lib.js
index ba7106ec77d..52cbb4d5d40 100644
--- a/translator/testFiles/kotlin_lib.js
+++ b/translator/testFiles/kotlin_lib.js
@@ -109,16 +109,15 @@
             current = current.superclass;
         }
         return true;
-    }
+    };
 
     var emptyFunction = function () {
-    }
+    };
 
     var Class = (function () {
 
         function subclass() {
         }
-
         ;
         function create() {
             var parent = null, properties = $A(arguments);
@@ -203,7 +202,7 @@
     var Trait = (function () {
 
         function add(object, source) {
-            properties = Object.keys(source);
+            var properties = Object.keys(source);
             for (var i = 0, length = properties.length; i < length; i++) {
                 var property = properties[i];
                 var value = source[property];
@@ -238,7 +237,17 @@
         };
     })();
 
-    Kotlin = {}
+    var object = (function () {
+        function create() {
+            var singletonClass = Class.create.apply(Class, arguments);
+            return new singletonClass;
+        }
+        return {
+            create:create
+        };
+    })();
+
+    Kotlin = {};
     Kotlin.Class = Class;
     Kotlin.Namespace = Namespace;
     Kotlin.Trait = Trait;
@@ -315,9 +324,9 @@
 
 
     Kotlin.parseInt =
-    function (str) {
-        return parseInt(str);
-    }
+        function (str) {
+            return parseInt(str);
+        }
     ;
 
     Kotlin.System = function () {
@@ -454,14 +463,26 @@
         {
             initialize:function () {
             },
-            compare:function () {
+            compare:function (el1, el2) {
                 throw new Kotlin.AbstractFunctionInvokationError();
             }
         }
     );
 
-    Kotlin.collectionsMax = function(col, comp) {
-
+    Kotlin.collectionsMax = function (col, comp) {
+        var it = col.iterator();
+        if (col.isEmpty()) {
+            //TODO: which exception?
+            throw Kotlin.Exception();
+        }
+        var max = it.next();
+        while (it.hasNext()) {
+            var el = it.next();
+            if (comp.compare(max, el) < 0) {
+                max = el;
+            }
+        }
+        return max;
     };
 
     Kotlin.StringBuilder = Kotlin.Class.create(
diff --git a/translator/testFiles/webDemoExamples2/cases/maze.kt b/translator/testFiles/webDemoExamples2/cases/maze.kt
index f6dbb9eed3e..f599ea9f829 100644
--- a/translator/testFiles/webDemoExamples2/cases/maze.kt
+++ b/translator/testFiles/webDemoExamples2/cases/maze.kt
@@ -31,10 +31,10 @@ import java.util.*
 fun findPath(maze : Maze) : List<#(Int, Int)>? {
     val previous = HashMap<#(Int, Int), #(Int, Int)>
 
-    val queue = LinkedList<#(Int, Int)>
+    val queue = ArrayList<#(Int, Int)>
     val visited = HashSet<#(Int, Int)>
 
-    queue.offer(maze.start)
+    queue.add(maze.start)
     visited.add(maze.start)
     while (!queue.isEmpty()) {
       val cell = queue.poll()