diff --git a/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClassFileDecompiler.java b/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClassFileDecompiler.java
index 9114b5da4e8..3305db1ff83 100644
--- a/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClassFileDecompiler.java
+++ b/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClassFileDecompiler.java
@@ -24,7 +24,7 @@ import com.intellij.psi.compiled.ClsStubBuilder;
 import org.jetbrains.annotations.NotNull;
 
 public class JetClassFileDecompiler extends ClassFileDecompilers.Full {
-    private final ClsStubBuilder stubBuilder = new JetClsStubBuilder();
+    private final ClsStubBuilder stubBuilder = new KotlinClsStubBuilder();
 
     @Override
     public boolean accepts(@NotNull VirtualFile file) {
diff --git a/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClsStubBuilder.java b/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClsStubBuilder.java
deleted file mode 100644
index a3354a9981e..00000000000
--- a/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/JetClsStubBuilder.java
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * 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.plugin.libraries;
-
-import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.psi.compiled.ClsStubBuilder;
-import com.intellij.psi.impl.compiled.ClassFileStubBuilder;
-import com.intellij.psi.impl.compiled.ClsFileImpl;
-import com.intellij.psi.stubs.PsiFileStub;
-import com.intellij.util.cls.ClsFormatException;
-import com.intellij.util.indexing.FileContent;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-
-public class JetClsStubBuilder extends ClsStubBuilder {
-    @Override
-    public int getStubVersion() {
-        return ClassFileStubBuilder.STUB_VERSION + 1;
-    }
-
-    @Nullable
-    @Override
-    public PsiFileStub<?> buildFileStub(@NotNull FileContent content) throws ClsFormatException {
-        VirtualFile file = content.getFile();
-
-        if (LibrariesPackage.isKotlinInternalCompiledFile(file)) {
-            return null;
-        }
-
-        return ClsFileImpl.buildFileStub(file, content.getContent());
-    }
-}
diff --git a/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/KotlinClsStubBuilder.kt b/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/KotlinClsStubBuilder.kt
new file mode 100644
index 00000000000..f6289f5b89e
--- /dev/null
+++ b/idea/idea-analysis/src/org/jetbrains/jet/plugin/libraries/KotlinClsStubBuilder.kt
@@ -0,0 +1,40 @@
+/*
+ * 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.plugin.libraries
+
+import com.intellij.openapi.vfs.VirtualFile
+import com.intellij.psi.compiled.ClsStubBuilder
+import com.intellij.psi.impl.compiled.ClassFileStubBuilder
+import com.intellij.psi.impl.compiled.ClsFileImpl
+import com.intellij.psi.stubs.PsiFileStub
+import com.intellij.util.cls.ClsFormatException
+import com.intellij.util.indexing.FileContent
+
+public class KotlinClsStubBuilder : ClsStubBuilder() {
+    override fun getStubVersion() = ClassFileStubBuilder.STUB_VERSION + 1
+
+    throws(javaClass<ClsFormatException>())
+    override fun buildFileStub(content: FileContent): PsiFileStub<*>? {
+        val file = content.getFile()
+
+        if (isKotlinInternalCompiledFile(file)) {
+            return null
+        }
+
+        return ClsFileImpl.buildFileStub(file, content.getContent())
+    }
+}