diff --git a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/types/KotlinToJavaTypesMap.java b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/types/KotlinToJavaTypesMap.java
index 82ae5dfbebc..be339b491f2 100644
--- a/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/types/KotlinToJavaTypesMap.java
+++ b/compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/types/KotlinToJavaTypesMap.java
@@ -18,13 +18,11 @@ package org.jetbrains.kotlin.resolve.jvm.types;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.descriptors.ClassDescriptor;
 import org.jetbrains.kotlin.name.ClassId;
 import org.jetbrains.kotlin.name.FqNameUnsafe;
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMapBuilder;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
-import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -44,16 +42,6 @@ public class KotlinToJavaTypesMap extends JavaToKotlinClassMapBuilder {
 
     private KotlinToJavaTypesMap() {
         init();
-        initPrimitives();
-    }
-
-    private void initPrimitives() {
-        for (JvmPrimitiveType type : JvmPrimitiveType.values()) {
-            register(
-                    KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME.child(type.getPrimitiveType().getTypeName()).toUnsafe(),
-                    ClassId.topLevel(type.getWrapperFqName())
-            );
-        }
     }
 
     /**
@@ -71,7 +59,7 @@ public class KotlinToJavaTypesMap extends JavaToKotlinClassMapBuilder {
     @Override
     protected void register(@NotNull ClassId javaClassId, @NotNull ClassDescriptor kotlinDescriptor, @NotNull Direction direction) {
         if (direction == Direction.BOTH || direction == Direction.KOTLIN_TO_JAVA) {
-            register(DescriptorUtils.getFqName(kotlinDescriptor), javaClassId);
+            map.put(DescriptorUtils.getFqName(kotlinDescriptor), javaClassId);
         }
     }
 
@@ -84,8 +72,4 @@ public class KotlinToJavaTypesMap extends JavaToKotlinClassMapBuilder {
         register(javaClassId, kotlinDescriptor, Direction.BOTH);
         register(javaClassId, kotlinMutableDescriptor, Direction.BOTH);
     }
-
-    private void register(@NotNull FqNameUnsafe kotlinFqName, @NotNull ClassId javaClassId) {
-        map.put(kotlinFqName, javaClassId);
-    }
 }
diff --git a/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMap.java b/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMap.java
index 5043c2c1f9c..0f153a8bdca 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMap.java
+++ b/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMap.java
@@ -25,7 +25,6 @@ import org.jetbrains.kotlin.name.ClassId;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.name.FqNameUnsafe;
 import org.jetbrains.kotlin.resolve.DescriptorUtils;
-import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType;
 
 import java.util.*;
 
@@ -37,15 +36,6 @@ public class JavaToKotlinClassMap extends JavaToKotlinClassMapBuilder implements
 
     private JavaToKotlinClassMap() {
         init();
-        initPrimitives();
-    }
-
-    private void initPrimitives() {
-        KotlinBuiltIns builtIns = KotlinBuiltIns.getInstance();
-
-        for (JvmPrimitiveType jvmType : JvmPrimitiveType.values()) {
-            register(ClassId.topLevel(jvmType.getWrapperFqName()), builtIns.getPrimitiveClassDescriptor(jvmType.getPrimitiveType()));
-        }
     }
 
     @Nullable
diff --git a/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMapBuilder.java b/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMapBuilder.java
index a54520e4e42..39b66057269 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMapBuilder.java
+++ b/core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMapBuilder.java
@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor;
 import org.jetbrains.kotlin.name.ClassId;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.name.Name;
+import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType;
 
 import java.lang.annotation.Annotation;
 import java.util.*;
@@ -56,6 +57,14 @@ public abstract class JavaToKotlinClassMapBuilder {
         register(Map.Entry.class, kotlinBuiltIns.getMapEntry(), kotlinBuiltIns.getMutableMapEntry());
         register(ListIterator.class, kotlinBuiltIns.getListIterator(), kotlinBuiltIns.getMutableListIterator());
 
+        for (JvmPrimitiveType jvmType : JvmPrimitiveType.values()) {
+            register(
+                    ClassId.topLevel(jvmType.getWrapperFqName()),
+                    kotlinBuiltIns.getPrimitiveClassDescriptor(jvmType.getPrimitiveType()),
+                    Direction.BOTH
+            );
+        }
+
         register(classId(Deprecated.class), kotlinBuiltIns.getDeprecatedAnnotation(), Direction.JAVA_TO_KOTLIN);
 
         register(classId(Void.class), kotlinBuiltIns.getNothing(), Direction.KOTLIN_TO_JAVA);
diff --git a/core/reflection.jvm/src/kotlin/reflect/jvm/internal/RuntimeTypeMapper.kt b/core/reflection.jvm/src/kotlin/reflect/jvm/internal/RuntimeTypeMapper.kt
index 156ad8665a8..08d90fcf862 100644
--- a/core/reflection.jvm/src/kotlin/reflect/jvm/internal/RuntimeTypeMapper.kt
+++ b/core/reflection.jvm/src/kotlin/reflect/jvm/internal/RuntimeTypeMapper.kt
@@ -23,7 +23,7 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.load.java.structure.reflect.classId
 import org.jetbrains.kotlin.name.ClassId
-import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.FqNameUnsafe
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMap
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMapBuilder
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMapBuilder.Direction.BOTH
@@ -36,28 +36,15 @@ import org.jetbrains.kotlin.types.JetType
 import org.jetbrains.kotlin.types.TypeUtils
 
 object RuntimeTypeMapper : JavaToKotlinClassMapBuilder() {
-    private val kotlinFqNameToJvmDesc = linkedMapOf<FqName, String>()
+    private val kotlinFqNameToJvmDesc = linkedMapOf<FqNameUnsafe, String>()
 
     init {
         init()
-        initPrimitives()
-    }
-
-    private fun initPrimitives() {
-        val builtIns = KotlinBuiltIns.getInstance()
-
-        for (type in JvmPrimitiveType.values()) {
-            recordKotlinToJvm(builtIns.getPrimitiveClassDescriptor(type.getPrimitiveType()), type.getDesc())
-        }
-    }
-
-    private fun recordKotlinToJvm(kotlinDescriptor: ClassDescriptor, jvmDesc: String) {
-        kotlinFqNameToJvmDesc[DescriptorUtils.getFqNameSafe(kotlinDescriptor)] = jvmDesc
     }
 
     override fun register(javaClassId: ClassId, kotlinDescriptor: ClassDescriptor, direction: JavaToKotlinClassMapBuilder.Direction) {
         if (direction == BOTH || direction == KOTLIN_TO_JAVA) {
-            recordKotlinToJvm(kotlinDescriptor, javaClassId.desc)
+            kotlinFqNameToJvmDesc[DescriptorUtils.getFqName(kotlinDescriptor)] = javaClassId.desc
         }
     }
 
@@ -81,20 +68,18 @@ object RuntimeTypeMapper : JavaToKotlinClassMapBuilder() {
         }
 
         val classDescriptor = classifier as ClassDescriptor
-        val fqNameUnsafe = DescriptorUtils.getFqName(classDescriptor)
+        val fqName = DescriptorUtils.getFqName(classDescriptor)
 
-        KotlinBuiltIns.getPrimitiveTypeByFqName(fqNameUnsafe)?.let { primitiveType ->
+        KotlinBuiltIns.getPrimitiveTypeByFqName(fqName)?.let { primitiveType ->
             val jvmType = JvmPrimitiveType.get(primitiveType)
             return if (TypeUtils.isNullableType(type)) ClassId.topLevel(jvmType.getWrapperFqName()).desc else jvmType.getDesc()
         }
 
-        KotlinBuiltIns.getPrimitiveTypeByArrayClassFqName(fqNameUnsafe)?.let { primitiveType ->
+        KotlinBuiltIns.getPrimitiveTypeByArrayClassFqName(fqName)?.let { primitiveType ->
             return "[" + JvmPrimitiveType.get(primitiveType).getDesc()
         }
 
-        if (fqNameUnsafe.isSafe()) {
-            kotlinFqNameToJvmDesc[fqNameUnsafe.toSafe()]?.let { return it }
-        }
+        kotlinFqNameToJvmDesc[fqName]?.let { return it }
 
         if (classDescriptor.isCompanionObject()) {
             IntrinsicObjects.mapType(classDescriptor)?.let { fqName ->