diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
index fac6074fc59..cbaafc3b0e6 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java
@@ -52,7 +52,6 @@ import org.jetbrains.jet.lang.resolve.constants.CompileTimeConstant;
 import org.jetbrains.jet.lang.resolve.java.AsmTypeConstants;
 import org.jetbrains.jet.lang.resolve.java.JvmAbi;
 import org.jetbrains.jet.lang.resolve.java.JvmAnnotationNames;
-import org.jetbrains.jet.lang.resolve.name.FqNameUnsafe;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.types.*;
 import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
@@ -350,8 +349,7 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         sw.writeSuperclassEnd();
 
         List<JetType> interfaceSupertypes = Lists.newArrayList();
-        FqNameUnsafe jetObjectFqName = JvmAbi.JET_OBJECT.getFqNameForClassNameWithoutDollars().toUnsafe();
-        boolean explicitJetObject = false;
+        boolean explicitKObject = false;
 
         for (JetDelegationSpecifier specifier : myClass.getDelegationSpecifiers()) {
             JetType superType = bindingContext.get(BindingContext.TYPE, specifier.getTypeReference());
@@ -361,19 +359,20 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
                 interfaceSupertypes.add(superType);
 
                 assert superClassDescriptor != null : "should be already checked by isInterface()";
-                if (jetObjectFqName.equals(DescriptorUtils.getFqName(superClassDescriptor))) {
-                    explicitJetObject = true;
+                if (JvmAbi.K_OBJECT.equalsTo(DescriptorUtils.getFqName(superClassDescriptor))) {
+                    explicitKObject = true;
                 }
             }
         }
 
         LinkedHashSet<String> superInterfaces = new LinkedHashSet<String>();
-        if (!explicitJetObject) {
+        if (!explicitKObject) {
+            Type kObject = asmTypeByFqNameWithoutInnerClasses(JvmAbi.K_OBJECT);
             sw.writeInterface();
-            sw.writeClassBegin(Type.getObjectType(JvmAbi.JET_OBJECT.getInternalName()));
+            sw.writeClassBegin(kObject);
             sw.writeClassEnd();
             sw.writeInterfaceEnd();
-            superInterfaces.add(JvmAbi.JET_OBJECT.getInternalName());
+            superInterfaces.add(kObject.getInternalName());
         }
 
         for (JetType supertype : interfaceSupertypes) {
diff --git a/compiler/testData/asJava/nullabilityAnnotations/Class.java b/compiler/testData/asJava/nullabilityAnnotations/Class.java
index 394923d8d0e..02944a909ca 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/Class.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/Class.java
@@ -1,4 +1,4 @@
-public final class Class implements jet.JetObject {
+public final class Class implements kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.Nullable
     private final java.lang.String nullableVal = "";
     @org.jetbrains.annotations.Nullable
@@ -71,4 +71,4 @@ public final class Class implements jet.JetObject {
 
     @org.jetbrains.annotations.NotNull
     public Class() { /* compiled code */ }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/ClassObjectField.java b/compiler/testData/asJava/nullabilityAnnotations/ClassObjectField.java
index 26b3180727f..60f5378a83c 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/ClassObjectField.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/ClassObjectField.java
@@ -1,4 +1,4 @@
-public final class ClassObjectField implements jet.JetObject {
+public final class ClassObjectField implements kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.Nullable
     public static final java.lang.String x = "";
     private static final java.lang.String y = "";
@@ -7,7 +7,7 @@ public final class ClassObjectField implements jet.JetObject {
     @org.jetbrains.annotations.NotNull
     public ClassObjectField() { /* compiled code */ }
 
-    public static final class object implements jet.JetObject {
+    public static final class object implements kotlin.jvm.internal.KObject {
         @org.jetbrains.annotations.Nullable
         public final java.lang.String getX() { /* compiled code */ }
 
@@ -15,4 +15,4 @@ public final class ClassObjectField implements jet.JetObject {
 
         private object() { /* compiled code */ }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructor.java b/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructor.java
index 63fa0808070..f781f98d627 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructor.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructor.java
@@ -1,4 +1,4 @@
-public final class ClassWithConstructor implements jet.JetObject {
+public final class ClassWithConstructor implements kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.NotNull
     public ClassWithConstructor(@org.jetbrains.annotations.Nullable @jet.runtime.typeinfo.JetValueParameter(name = "nullable", type = "?") java.lang.String nullable, @org.jetbrains.annotations.NotNull @jet.runtime.typeinfo.JetValueParameter(name = "notNull") java.lang.String notNull) { /* compiled code */ }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructorAndProperties.java b/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructorAndProperties.java
index 97b3230151b..b59925f9a57 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructorAndProperties.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/ClassWithConstructorAndProperties.java
@@ -1,4 +1,4 @@
-public final class ClassWithConstructorAndProperties implements jet.JetObject {
+public final class ClassWithConstructorAndProperties implements kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.Nullable
     private final java.lang.String nullable;
     @org.jetbrains.annotations.NotNull
@@ -12,4 +12,4 @@ public final class ClassWithConstructorAndProperties implements jet.JetObject {
 
     @org.jetbrains.annotations.NotNull
     public ClassWithConstructorAndProperties(@org.jetbrains.annotations.Nullable @jet.runtime.typeinfo.JetValueParameter(name = "nullable", type = "?") java.lang.String nullable, @org.jetbrains.annotations.NotNull @jet.runtime.typeinfo.JetValueParameter(name = "notNull") java.lang.String notNull) { /* compiled code */ }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/Generic.java b/compiler/testData/asJava/nullabilityAnnotations/Generic.java
index 068c72311df..2467ff5720e 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/Generic.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/Generic.java
@@ -1,4 +1,4 @@
-public interface Generic <N, NN> extends jet.JetObject {
+public interface Generic <N, NN> extends kotlin.jvm.internal.KObject {
     N a(@jet.runtime.typeinfo.JetValueParameter(name = "n") N n);
 
     @org.jetbrains.annotations.NotNull
@@ -9,4 +9,4 @@ public interface Generic <N, NN> extends jet.JetObject {
 
     @org.jetbrains.annotations.Nullable
     NN b1(@org.jetbrains.annotations.Nullable @jet.runtime.typeinfo.JetValueParameter(name = "nn", type = "?") NN nn);
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/Primitives.java b/compiler/testData/asJava/nullabilityAnnotations/Primitives.java
index 0f3a81a7a42..e9e92214695 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/Primitives.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/Primitives.java
@@ -1,4 +1,4 @@
-public interface Primitives extends jet.JetObject {
+public interface Primitives extends kotlin.jvm.internal.KObject {
     int $$int /* Real name is 'int' */(@jet.runtime.typeinfo.JetValueParameter(name = "x") int x);
 
     @org.jetbrains.annotations.Nullable
@@ -40,4 +40,4 @@ public interface Primitives extends jet.JetObject {
     float getFloat();
 
     double getDouble();
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/PrivateInClass.java b/compiler/testData/asJava/nullabilityAnnotations/PrivateInClass.java
index bdc456393f6..32bf3192ac3 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/PrivateInClass.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/PrivateInClass.java
@@ -1,4 +1,4 @@
-public final class PrivateInClass implements jet.JetObject {
+public final class PrivateInClass implements kotlin.jvm.internal.KObject {
     private final java.lang.String nn = "";
     private final java.lang.String n = "";
 
@@ -9,4 +9,4 @@ public final class PrivateInClass implements jet.JetObject {
     private final java.lang.String bar(@jet.runtime.typeinfo.JetValueParameter(name = "a") java.lang.String a, @jet.runtime.typeinfo.JetValueParameter(name = "b", type = "?") java.lang.String b) { /* compiled code */ }
 
     private PrivateInClass(@jet.runtime.typeinfo.JetValueParameter(name = "s", type = "?") java.lang.String s) { /* compiled code */ }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/PrivateInTrait.java b/compiler/testData/asJava/nullabilityAnnotations/PrivateInTrait.java
index 699ae9fea12..f09cd14a03b 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/PrivateInTrait.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/PrivateInTrait.java
@@ -1,4 +1,4 @@
-public interface PrivateInTrait extends jet.JetObject {
+public interface PrivateInTrait extends kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.NotNull
     java.lang.String getNn();
 
@@ -7,4 +7,4 @@ public interface PrivateInTrait extends jet.JetObject {
 
     @org.jetbrains.annotations.Nullable
     java.lang.String bar(@org.jetbrains.annotations.NotNull @jet.runtime.typeinfo.JetValueParameter(name = "a") java.lang.String a, @org.jetbrains.annotations.Nullable @jet.runtime.typeinfo.JetValueParameter(name = "b", type = "?") java.lang.String b);
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/Synthetic.java b/compiler/testData/asJava/nullabilityAnnotations/Synthetic.java
index d1f6a7e46c0..4bbf5fb52b9 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/Synthetic.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/Synthetic.java
@@ -1,14 +1,14 @@
-public final class Synthetic implements jet.JetObject {
+public final class Synthetic implements kotlin.jvm.internal.KObject {
     private final void foo() { /* compiled code */ }
 
     @org.jetbrains.annotations.NotNull
     public Synthetic() { /* compiled code */ }
 
-    public final class Inner implements jet.JetObject {
+    public final class Inner implements kotlin.jvm.internal.KObject {
         @org.jetbrains.annotations.NotNull
         public final void test() { /* compiled code */ }
 
         @org.jetbrains.annotations.NotNull
         public Inner() { /* compiled code */ }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/Trait.java b/compiler/testData/asJava/nullabilityAnnotations/Trait.java
index 520787fb8ca..ebe1ccec524 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/Trait.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/Trait.java
@@ -1,4 +1,4 @@
-public interface Trait extends jet.JetObject {
+public interface Trait extends kotlin.jvm.internal.KObject {
     @org.jetbrains.annotations.NotNull
     java.lang.String notNull(@org.jetbrains.annotations.NotNull @jet.runtime.typeinfo.JetValueParameter(name = "a") java.lang.String a);
 
@@ -36,4 +36,4 @@ public interface Trait extends jet.JetObject {
 
     @org.jetbrains.annotations.NotNull
     void setNotNullVar(@org.jetbrains.annotations.NotNull @jet.runtime.typeinfo.JetValueParameter(name = "<set-?>") java.lang.String p);
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/asJava/nullabilityAnnotations/TraitClassObjectField.java b/compiler/testData/asJava/nullabilityAnnotations/TraitClassObjectField.java
index 77923e6da3a..b089bc0e449 100644
--- a/compiler/testData/asJava/nullabilityAnnotations/TraitClassObjectField.java
+++ b/compiler/testData/asJava/nullabilityAnnotations/TraitClassObjectField.java
@@ -1,9 +1,9 @@
-public interface TraitClassObjectField extends jet.JetObject {
+public interface TraitClassObjectField extends kotlin.jvm.internal.KObject {
     TraitClassObjectField.object object$;
     @org.jetbrains.annotations.Nullable
     java.lang.String x = "";
 
-    static final class object implements jet.JetObject {
+    static final class object implements kotlin.jvm.internal.KObject {
         @org.jetbrains.annotations.Nullable
         private final java.lang.String x = "";
         private final java.lang.String y = "";
@@ -15,4 +15,4 @@ public interface TraitClassObjectField extends jet.JetObject {
 
         private object() { /* compiled code */ }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt b/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
index d20e96e2b41..f01bd39ef95 100644
--- a/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
+++ b/compiler/testData/codegen/boxWithStdlib/regressions/getGenericInterfaces.kt
@@ -1,5 +1,7 @@
 // KT-4485 getGenericInterfaces vs getInterfaces for kotlin classes
 
+import kotlin.jvm.internal.KObject
+
 class SimpleClass
 
 class ClassWithNonGenericSuperInterface: Cloneable
@@ -8,7 +10,7 @@ class ClassWithGenericSuperInterface: java.util.Comparator<String> {
     override fun compare(a: String, b: String): Int = 0
 }
 
-class ExplicitJetObject: java.util.Comparator<String>, JetObject {
+class ExplicitKObject: java.util.Comparator<String>, KObject {
     override fun compare(a: String, b: String): Int = 0
 }
 
@@ -24,6 +26,6 @@ fun box(): String {
     check(javaClass<SimpleClass>())
     check(javaClass<ClassWithNonGenericSuperInterface>())
     check(javaClass<ClassWithGenericSuperInterface>())
-    check(javaClass<ExplicitJetObject>())
+    check(javaClass<ExplicitKObject>())
     return "OK"
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/writeSignature/declarationSiteVariance/MappedSupertypeWithVariance.kt b/compiler/testData/writeSignature/declarationSiteVariance/MappedSupertypeWithVariance.kt
index 8083856a511..b3dc2dbb72b 100644
--- a/compiler/testData/writeSignature/declarationSiteVariance/MappedSupertypeWithVariance.kt
+++ b/compiler/testData/writeSignature/declarationSiteVariance/MappedSupertypeWithVariance.kt
@@ -3,4 +3,4 @@ trait Derived<A>: List<A>
 
 // class: Derived
 // jvm signature:     Derived
-// generic signature: <A:Ljava/lang/Object;>Ljava/lang/Object;Ljet/JetObject;Ljava/util/List<TA;>;
+// generic signature: <A:Ljava/lang/Object;>Ljava/lang/Object;Lkotlin/jvm/internal/KObject;Ljava/util/List<TA;>;
diff --git a/compiler/testData/writeSignature/declarationSiteVariance/SuperClassWithVariance.kt b/compiler/testData/writeSignature/declarationSiteVariance/SuperClassWithVariance.kt
index 46827b87e42..8d672aee6c7 100644
--- a/compiler/testData/writeSignature/declarationSiteVariance/SuperClassWithVariance.kt
+++ b/compiler/testData/writeSignature/declarationSiteVariance/SuperClassWithVariance.kt
@@ -4,4 +4,4 @@ class Derived<A, B, C>: Base<A, B, C>()
 
 // class: Derived
 // jvm signature:     Derived
-// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>LBase<TA;TB;TC;>;Ljet/JetObject;
+// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>LBase<TA;TB;TC;>;Lkotlin/jvm/internal/KObject;
diff --git a/compiler/testData/writeSignature/declarationSiteVariance/SuperTraitWithVariance.kt b/compiler/testData/writeSignature/declarationSiteVariance/SuperTraitWithVariance.kt
index 85e99257517..5315bec17a3 100644
--- a/compiler/testData/writeSignature/declarationSiteVariance/SuperTraitWithVariance.kt
+++ b/compiler/testData/writeSignature/declarationSiteVariance/SuperTraitWithVariance.kt
@@ -4,4 +4,4 @@ class Derived<A, B, C>: Base<A, B, C>
 
 // class: Derived
 // jvm signature:     Derived
-// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>Ljava/lang/Object;Ljet/JetObject;LBase<TA;TB;TC;>;
+// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>Ljava/lang/Object;Lkotlin/jvm/internal/KObject;LBase<TA;TB;TC;>;
diff --git a/compiler/testData/writeSignature/declarationSiteVariance/SuperTypeWithVarianceInArguments.kt b/compiler/testData/writeSignature/declarationSiteVariance/SuperTypeWithVarianceInArguments.kt
index 3be3c1bf1b9..d334e6a2404 100644
--- a/compiler/testData/writeSignature/declarationSiteVariance/SuperTypeWithVarianceInArguments.kt
+++ b/compiler/testData/writeSignature/declarationSiteVariance/SuperTypeWithVarianceInArguments.kt
@@ -5,4 +5,4 @@ class Derived<A, B, C>: Intermediate<Base<A, B, C>>
 
 // class: Derived
 // jvm signature:     Derived
-// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>Ljava/lang/Object;Ljet/JetObject;LIntermediate<LBase<TA;-TB;+TC;>;>;
+// generic signature: <A:Ljava/lang/Object;B:Ljava/lang/Object;C:Ljava/lang/Object;>Ljava/lang/Object;Lkotlin/jvm/internal/KObject;LIntermediate<LBase<TA;-TB;+TC;>;>;
diff --git a/compiler/tests/org/jetbrains/jet/codegen/AnnotationGenTest.java b/compiler/tests/org/jetbrains/jet/codegen/AnnotationGenTest.java
index 93579252f3b..2bc226d079f 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/AnnotationGenTest.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/AnnotationGenTest.java
@@ -235,7 +235,7 @@ public class AnnotationGenTest extends CodegenTestCase {
         assertTrue(aClass.isAnnotation());
         assertEquals(2, interfaces.length);
         assertEquals(
-                Sets.newHashSet("java.lang.annotation.Annotation", "jet.JetObject"),
+                Sets.newHashSet("java.lang.annotation.Annotation", "kotlin.jvm.internal.KObject"),
                 Sets.newHashSet(interfaces[0].getName(), interfaces[1].getName())
         );
     }
diff --git a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/JvmAbi.java b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/JvmAbi.java
index d4ae2ab86b4..7f1301c212d 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/JvmAbi.java
+++ b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/JvmAbi.java
@@ -46,7 +46,7 @@ public final class JvmAbi {
     public static final String INSTANCE_FIELD = "instance$";
     public static final String CLASS_OBJECT_FIELD = "object$";
 
-    public static final JvmClassName JET_OBJECT = JvmClassName.byFqNameWithoutInnerClasses("jet.JetObject");
+    public static final FqName K_OBJECT = new FqName("kotlin.jvm.internal.KObject");
 
     public static boolean isClassObjectFqName(@NotNull FqName fqName) {
         return fqName.lastSegmentIs(Name.identifier(CLASS_OBJECT_CLASS_NAME));
diff --git a/core/runtime.jvm/src/jet/JetObject.java b/core/runtime.jvm/src/kotlin/jvm/internal/KObject.java
similarity index 91%
rename from core/runtime.jvm/src/jet/JetObject.java
rename to core/runtime.jvm/src/kotlin/jvm/internal/KObject.java
index e5ca29dac3f..e59d02e617a 100644
--- a/core/runtime.jvm/src/jet/JetObject.java
+++ b/core/runtime.jvm/src/kotlin/jvm/internal/KObject.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package jet;
+package kotlin.jvm.internal;
 
-public interface JetObject {
+public interface KObject {
 }
diff --git a/idea/src/org/jetbrains/jet/plugin/versions/KotlinRuntimeLibraryUtil.java b/idea/src/org/jetbrains/jet/plugin/versions/KotlinRuntimeLibraryUtil.java
index 0a6f67ad112..ece84d3631b 100644
--- a/idea/src/org/jetbrains/jet/plugin/versions/KotlinRuntimeLibraryUtil.java
+++ b/idea/src/org/jetbrains/jet/plugin/versions/KotlinRuntimeLibraryUtil.java
@@ -19,7 +19,6 @@ package org.jetbrains.jet.plugin.versions;
 import com.google.common.base.Predicate;
 import com.google.common.collect.Collections2;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.module.Module;
@@ -60,7 +59,6 @@ import java.util.Set;
 
 import static com.intellij.util.PathUtil.getLocalFile;
 import static com.intellij.util.PathUtil.getLocalPath;
-
 import static org.jetbrains.jet.plugin.versions.OutdatedKotlinRuntimeNotification.showRuntimeJarNotFoundDialog;
 
 public class KotlinRuntimeLibraryUtil {
@@ -156,12 +154,9 @@ public class KotlinRuntimeLibraryUtil {
 
         ImmutableList<String> candidateClassNames = ImmutableList.of(
                 kotlinPackageClassFqName,
-                // For built-ins module in Kotlin project
                 "jet.Unit",
                 // For older versions
-                "kotlin.namespace",
-                // For really old versions
-                "jet.JetObject"
+                "kotlin.namespace"
         );
 
         for (String className : candidateClassNames) {