diff --git a/core/descriptors/src/org/jetbrains/jet/lang/descriptors/PackageFragmentProviderImpl.kt b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/PackageFragmentProviderImpl.kt
new file mode 100644
index 00000000000..2dd955ae9a1
--- /dev/null
+++ b/core/descriptors/src/org/jetbrains/jet/lang/descriptors/PackageFragmentProviderImpl.kt
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2010-2014 JetBrains s.r.o.
+ *
+ * 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.
+ */
+
+package org.jetbrains.jet.lang.descriptors
+
+import org.jetbrains.jet.lang.resolve.name.FqName
+import org.jetbrains.jet.lang.resolve.name.Name
+
+public class PackageFragmentProviderImpl(
+        private val packageFragments: Collection<PackageFragmentDescriptor>
+) : PackageFragmentProvider {
+    override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor> =
+            packageFragments.filter { it.fqName == fqName }
+
+    override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> =
+            packageFragments.stream()
+                    .map { it.fqName }
+                    .filter { !it.isRoot() && it.parent() == fqName }
+                    .toList()
+}
diff --git a/core/descriptors/src/org/jetbrains/jet/lang/types/lang/BuiltinsPackageFragment.kt b/core/descriptors/src/org/jetbrains/jet/lang/types/lang/BuiltinsPackageFragment.kt
index 74f9ce827b9..b7cc9f2c862 100644
--- a/core/descriptors/src/org/jetbrains/jet/lang/types/lang/BuiltinsPackageFragment.kt
+++ b/core/descriptors/src/org/jetbrains/jet/lang/types/lang/BuiltinsPackageFragment.kt
@@ -20,15 +20,13 @@ import org.jetbrains.jet.descriptors.serialization.*
 import org.jetbrains.jet.descriptors.serialization.descriptors.AnnotationAndConstantLoader
 import org.jetbrains.jet.descriptors.serialization.descriptors.DeserializedPackageMemberScope
 import org.jetbrains.jet.lang.descriptors.ModuleDescriptor
-import org.jetbrains.jet.lang.descriptors.PackageFragmentDescriptor
 import org.jetbrains.jet.lang.descriptors.PackageFragmentProvider
+import org.jetbrains.jet.lang.descriptors.PackageFragmentProviderImpl
 import org.jetbrains.jet.lang.descriptors.impl.PackageFragmentDescriptorImpl
 import org.jetbrains.jet.lang.resolve.name.ClassId
-import org.jetbrains.jet.lang.resolve.name.FqName
 import org.jetbrains.jet.lang.resolve.name.Name
 import org.jetbrains.jet.storage.StorageManager
 import java.io.DataInputStream
-import java.io.IOException
 import java.io.InputStream
 import java.util.ArrayList
 import org.jetbrains.jet.descriptors.serialization.context.DeserializationComponents
@@ -38,7 +36,7 @@ class BuiltinsPackageFragment(storageManager: StorageManager, module: ModuleDesc
 
     private val nameResolver = NameSerializationUtil.deserializeNameResolver(getStream(BuiltInsSerializationUtil.getNameTableFilePath(fqName)))
 
-    public val provider: PackageFragmentProvider = BuiltinsPackageFragmentProvider()
+    public val provider: PackageFragmentProvider = PackageFragmentProviderImpl(listOf(this))
 
     private val members: DeserializedPackageMemberScope =
         DeserializedPackageMemberScope(
@@ -53,47 +51,28 @@ class BuiltinsPackageFragment(storageManager: StorageManager, module: ModuleDesc
         )
 
     private fun loadPackage(): ProtoBuf.Package {
-        val packageFilePath = BuiltInsSerializationUtil.getPackageFilePath(fqName)
-        val stream = getStream(packageFilePath)
-        try {
-            return ProtoBuf.Package.parseFrom(stream)
-        }
-        catch (e: IOException) {
-            throw IllegalStateException(e)
-        }
-
+        val stream = getStream(BuiltInsSerializationUtil.getPackageFilePath(fqName))
+        return ProtoBuf.Package.parseFrom(stream)
     }
 
     private fun readClassNames(): List<Name> {
-        val `in` = getStream(BuiltInsSerializationUtil.getClassNamesFilePath(fqName))
-        val data = DataInputStream(`in`)
-        try {
+        val stream = getStream(BuiltInsSerializationUtil.getClassNamesFilePath(fqName))
+        return DataInputStream(stream).use { data ->
             val size = data.readInt()
             val result = ArrayList<Name>(size)
-            for (i in 0..size - 1) {
+            size.times {
                 result.add(nameResolver.getName(data.readInt()))
             }
-            return result
-        }
-        finally {
-            data.close()
+            result
         }
     }
 
     override fun getMemberScope() = members
 
-    private fun getStream(path: String) = getStreamNullable(path) ?: throw IllegalStateException("Resource not found in classpath: " + path)
+    private fun getStream(path: String) = getStreamNullable(path) ?: throw IllegalStateException("Resource not found in classpath: $path")
 
     private fun getStreamNullable(path: String): InputStream? = javaClass<KotlinBuiltIns>().getClassLoader().getResourceAsStream(path)
 
-    private inner class BuiltinsPackageFragmentProvider : PackageFragmentProvider {
-        override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor>
-                = if (KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME == fqName) listOf(this@BuiltinsPackageFragment) else listOf()
-
-        override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName>
-                = if (fqName.isRoot()) setOf(KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME) else listOf()
-    }
-
     private inner class BuiltInsClassDataFinder : ClassDataFinder {
         override fun findClassData(classId: ClassId): ClassData? {
             val metadataPath = BuiltInsSerializationUtil.getClassMetadataPath(classId) ?: return null