diff --git a/idea/src/META-INF/plugin.xml b/idea/src/META-INF/plugin.xml
index 743a36840fb..a7a0110cd57 100644
--- a/idea/src/META-INF/plugin.xml
+++ b/idea/src/META-INF/plugin.xml
@@ -1,7 +1,7 @@
 <idea-plugin version="2">
   <name>Kotlin</name>
   <description>Kotlin language support</description>
-  <version>@snapshot@</version>
+  <version>snapshot</version>
   <vendor>JetBrains</vendor>
 
   <depends optional="true">JUnit</depends>
@@ -153,6 +153,8 @@
       <stubIndex implementation="org.jetbrains.jet.plugin.stubindex.JetShortFunctionNameIndex"/>
       <stubIndex implementation="org.jetbrains.jet.plugin.stubindex.JetExtensionFunctionNameIndex"/>
 
+      <contentBasedClassFileProcessor implementation="org.jetbrains.jet.plugin.JetContentBasedFileSubstitutor" />
+
       <editorNotificationProvider implementation="org.jetbrains.jet.plugin.quickfix.ConfigureKotlinLibraryNotificationProvider"/>
 
       <psi.treeChangePreprocessor implementation="org.jetbrains.jet.asJava.JetCodeBlockModificationListener"/>
diff --git a/idea/src/org/jetbrains/jet/plugin/JetContentBasedFileSubstitutor.java b/idea/src/org/jetbrains/jet/plugin/JetContentBasedFileSubstitutor.java
new file mode 100644
index 00000000000..3f8bfa633af
--- /dev/null
+++ b/idea/src/org/jetbrains/jet/plugin/JetContentBasedFileSubstitutor.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2000-2012 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;
+
+import com.intellij.ide.highlighter.JavaClassFileType;
+import com.intellij.lang.Language;
+import com.intellij.openapi.fileTypes.ContentBasedClassFileProcessor;
+import com.intellij.openapi.fileTypes.FileTypeManager;
+import com.intellij.openapi.fileTypes.SyntaxHighlighter;
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.io.StreamUtil;
+import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.PsiAnnotation;
+import com.intellij.psi.PsiClass;
+import com.intellij.psi.PsiModifierList;
+import com.intellij.psi.impl.compiled.ClassFileStubBuilder;
+import com.intellij.psi.impl.compiled.ClsAnnotationImpl;
+import com.intellij.psi.impl.java.stubs.PsiJavaFileStub;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * @author Evgeny Gerashchenko
+ * @since 2/15/12
+ */
+public class JetContentBasedFileSubstitutor implements ContentBasedClassFileProcessor {
+
+    @Override
+    public boolean isApplicable(Project project, VirtualFile vFile) {
+        return isKotlinClass(project, vFile);
+    }
+
+    @NotNull
+    @Override
+    public String obtainFileText(Project project, VirtualFile file) {
+        return file.getNameWithoutExtension();
+    }
+
+    @Override
+    public Language obtainLanguageForFile(VirtualFile file) {
+        if (!file.getNameWithoutExtension().contains("$")) {
+            return JetLanguage.INSTANCE;
+        }
+        return null;
+    }
+
+    @NotNull
+    @Override
+    public SyntaxHighlighter createHighlighter(Project project, VirtualFile vFile) {
+        return JetHighlighter.PROVIDER.create(JetFileType.INSTANCE, project, vFile);
+    }
+
+    private static boolean isKotlinClass(Project project, VirtualFile file) {
+        if (!FileTypeManager.getInstance().isFileOfType(file, JavaClassFileType.INSTANCE)) {
+            return false;
+        }
+        PsiJavaFileStub javaStub = getJavaStub(project, file);
+        if (javaStub == null) {
+            return false;
+        }
+        // TODO multiple?
+        if (javaStub.getClasses().length != 1) {
+            throw new AssertionError("Multiple classes in file: " + Arrays.toString(javaStub.getClasses()));
+        }
+        PsiClass psiClass = javaStub.getClasses()[0];
+        // TODO add better check
+        if (psiClass.getName().equals("namespace")) {
+            return true;
+        }
+        PsiModifierList modifierList = psiClass.getModifierList();
+        if (modifierList != null) {
+            for (PsiAnnotation annotation : modifierList.getAnnotations()) {
+                if (annotation instanceof ClsAnnotationImpl) {
+                    if (((ClsAnnotationImpl) annotation).getStub().getText().startsWith("@jet.runtime.typeinfo.JetClass")) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
+    private static PsiJavaFileStub getJavaStub(Project project, VirtualFile file) {
+        try {
+            byte[] bytes = StreamUtil.loadFromStream(file.getInputStream());
+            return (PsiJavaFileStub) new ClassFileStubBuilder().buildStubTree(file, bytes, project);
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+
+}
+-