diff --git a/js/js.libraries/src/core/javalang.kt b/js/js.libraries/src/core/javalang.kt
index 2770a1c32ec..b7e03bf2ef2 100644
--- a/js/js.libraries/src/core/javalang.kt
+++ b/js/js.libraries/src/core/javalang.kt
@@ -1,5 +1,8 @@
 package java.lang
 
+library
+open public class Error(message: String? = null): Throwable(message) {}
+
 library
 open public class Exception(message: String? = null): Throwable(message) {}
 
diff --git a/js/js.translator/src/org/jetbrains/kotlin/js/translate/context/StandardClasses.java b/js/js.translator/src/org/jetbrains/kotlin/js/translate/context/StandardClasses.java
index 4e707e9761f..d2bc2778806 100644
--- a/js/js.translator/src/org/jetbrains/kotlin/js/translate/context/StandardClasses.java
+++ b/js/js.translator/src/org/jetbrains/kotlin/js/translate/context/StandardClasses.java
@@ -121,6 +121,8 @@ public final class StandardClasses {
         standardClasses.declare().forFQ("kotlin.Enum").kotlinClass("Enum");
 
         standardClasses.declare().forFQ("kotlin.Comparable").kotlinClass("Comparable");
+
+        standardClasses.declare().forFQ("koltin.Throwable").kotlinClass("Throwable");
     }
 
 
diff --git a/js/js.translator/testData/kotlin_lib.js b/js/js.translator/testData/kotlin_lib.js
index 30c968e6a84..ed6df120ce5 100644
--- a/js/js.translator/testData/kotlin_lib.js
+++ b/js/js.translator/testData/kotlin_lib.js
@@ -178,7 +178,8 @@
         return new Kotlin.Progression(from, to, -1);
     };
 
-    Kotlin.Exception = Error;
+    Kotlin.Throwable = Error;
+
 
     function createClassNowWithMessage(base) {
         return Kotlin.createClassNow(base,
@@ -189,6 +190,8 @@
                );
     }
 
+    Kotlin.Error = createClassNowWithMessage(Kotlin.Throwable);
+    Kotlin.Exception = createClassNowWithMessage(Kotlin.Throwable);
     Kotlin.RuntimeException = createClassNowWithMessage(Kotlin.Exception);
     Kotlin.NullPointerException = createClassNowWithMessage(Kotlin.RuntimeException);
     Kotlin.NoSuchElementException = createClassNowWithMessage(Kotlin.RuntimeException);
@@ -386,7 +389,7 @@
         },
         clear: function () {
             // TODO: implement with mutable iterator
-            throw new Kotlin.UnsupportedOperationException("Not implemented yet, see KT-7809");
+            throw new Kotlin.NotImplementedError("Not implemented yet, see KT-7809");
         },
         containsAll_4fm7v2$: function (c) {
             var it = c.iterator();
@@ -464,7 +467,7 @@
         },
         addAll_9cca64$: function (index, collection) {
             // TODO: implement
-            throw new Kotlin.UnsupportedOperationException("Not implemented yet, see KT-7809");
+            throw new Kotlin.NotImplementedError("Not implemented yet, see KT-7809");
         },
         remove_za3rmp$: function (o) {
             var index = this.indexOf_za3rmp$(o);
@@ -476,7 +479,7 @@
         },
         clear: function () {
             // TODO: implement with remove range
-            throw new Kotlin.UnsupportedOperationException("Not implemented yet, see KT-7809");
+            throw new Kotlin.NotImplementedError("Not implemented yet, see KT-7809");
         },
         contains_za3rmp$: function (o) {
             return this.indexOf_za3rmp$(o) !== -1;