diff --git a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/KotlinClassFileHeader.java b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/KotlinClassFileHeader.java
index 85a899c0b9e..8815cea621f 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/KotlinClassFileHeader.java
+++ b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/KotlinClassFileHeader.java
@@ -36,63 +36,45 @@ import java.util.List;
 import static org.jetbrains.asm4.ClassReader.*;
 import static org.jetbrains.jet.lang.resolve.java.AbiVersionUtil.isAbiVersionCompatible;
 
-public final class KotlinClassFileHeader {
+public abstract class KotlinClassFileHeader {
     private static final Logger LOG = Logger.getInstance(KotlinClassFileHeader.class);
 
     @Nullable
     public static KotlinClassFileHeader readKotlinHeaderFromClassFile(@NotNull VirtualFile virtualFile) {
         try {
             ClassReader reader = new ClassReader(virtualFile.contentsToByteArray());
-            ReadDataFromAnnotationVisitor visitor = new ReadDataFromAnnotationVisitor();
-            reader.accept(visitor, SKIP_CODE | SKIP_FRAMES | SKIP_DEBUG);
-            if (visitor.foundType == null) {
+            ReadDataFromAnnotationVisitor v = new ReadDataFromAnnotationVisitor();
+            reader.accept(v, SKIP_CODE | SKIP_FRAMES | SKIP_DEBUG);
+            if (v.foundType == null) {
                 return null;
             }
-            if (visitor.fqName == null) {
+            if (v.fqName == null) {
                 LOG.error("File doesn't have a class name: " + virtualFile);
                 return null;
             }
-            return new KotlinClassFileHeader(visitor.version, visitor.annotationData, visitor.foundType, visitor.fqName);
+
+            switch (v.foundType) {
+                case CLASS:
+                    return SerializedDataHeader.create(v.version, v.annotationData, SerializedDataHeader.Kind.CLASS, v.fqName);
+                case PACKAGE:
+                    return SerializedDataHeader.create(v.version, v.annotationData, SerializedDataHeader.Kind.PACKAGE, v.fqName);
+                case OLD_CLASS:
+                case OLD_PACKAGE:
+                    return new OldAnnotationHeader(v.fqName);
+                default:
+                    throw new UnsupportedOperationException("Unknown HeaderType: " + v.foundType);
+            }
         }
         catch (IOException e) {
             throw new RuntimeException(e);
         }
     }
 
-    @SuppressWarnings("deprecation")
-    public enum HeaderType {
-        CLASS(JvmAnnotationNames.KOTLIN_CLASS),
-        PACKAGE(JvmAnnotationNames.KOTLIN_PACKAGE),
-        OLD_CLASS(JvmAnnotationNames.OLD_JET_CLASS_ANNOTATION),
-        OLD_PACKAGE(JvmAnnotationNames.OLD_JET_PACKAGE_CLASS_ANNOTATION);
-
-        @NotNull
-        private final JvmClassName annotation;
-
-        private HeaderType(@NotNull JvmClassName annotation) {
-            this.annotation = annotation;
-        }
-
-        @Nullable
-        private static HeaderType byDescriptor(@NotNull String desc) {
-            for (HeaderType headerType : HeaderType.values()) {
-                if (desc.equals(headerType.annotation.getDescriptor())) {
-                    return headerType;
-                }
-            }
-            return null;
-        }
-    }
-
     private final int version;
-    private final String[] annotationData;
-    private final HeaderType type;
     private final FqName fqName;
 
-    private KotlinClassFileHeader(int version, @Nullable String[] annotationData, @NotNull HeaderType type, @NotNull FqName fqName) {
+    protected KotlinClassFileHeader(int version, @NotNull FqName fqName) {
         this.version = version;
-        this.annotationData = annotationData;
-        this.type = type;
         this.fqName = fqName;
     }
 
@@ -100,20 +82,6 @@ public final class KotlinClassFileHeader {
         return version;
     }
 
-    @Nullable
-    public String[] getAnnotationData() {
-        if (isCompatibleKotlinCompiledFile() && annotationData == null) {
-            LOG.error("Kotlin annotation " + type + " is incorrect for class: " + fqName);
-            return null;
-        }
-        return annotationData;
-    }
-
-    @NotNull
-    public HeaderType getType() {
-        return type;
-    }
-
     /**
      * @return FQ name for class header or package class FQ name for package header (e.g. <code>test.TestPackage</code>)
      */
@@ -126,10 +94,35 @@ public final class KotlinClassFileHeader {
      * @return true if this is a header for compiled Kotlin file with correct abi version which can be processed by compiler or the IDE
      */
     public boolean isCompatibleKotlinCompiledFile() {
-        return (type == HeaderType.CLASS || type == HeaderType.PACKAGE) && isAbiVersionCompatible(version);
+        return isAbiVersionCompatible(version);
     }
 
     private static class ReadDataFromAnnotationVisitor extends ClassVisitor {
+        @SuppressWarnings("deprecation")
+        private enum HeaderType {
+            CLASS(JvmAnnotationNames.KOTLIN_CLASS),
+            PACKAGE(JvmAnnotationNames.KOTLIN_PACKAGE),
+            OLD_CLASS(JvmAnnotationNames.OLD_JET_CLASS_ANNOTATION),
+            OLD_PACKAGE(JvmAnnotationNames.OLD_JET_PACKAGE_CLASS_ANNOTATION);
+
+            @NotNull
+            private final JvmClassName annotation;
+
+            private HeaderType(@NotNull JvmClassName annotation) {
+                this.annotation = annotation;
+            }
+
+            @Nullable
+            private static HeaderType byDescriptor(@NotNull String desc) {
+                for (HeaderType headerType : HeaderType.values()) {
+                    if (desc.equals(headerType.annotation.getDescriptor())) {
+                        return headerType;
+                    }
+                }
+                return null;
+            }
+        }
+
         private int version = AbiVersionUtil.INVALID_VERSION;
         @Nullable
         private String[] annotationData = null;
diff --git a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/OldAnnotationHeader.java b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/OldAnnotationHeader.java
new file mode 100644
index 00000000000..f29d92fd711
--- /dev/null
+++ b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/OldAnnotationHeader.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2010-2013 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.resolve.java.header;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.lang.resolve.java.AbiVersionUtil;
+import org.jetbrains.jet.lang.resolve.name.FqName;
+
+public class OldAnnotationHeader extends KotlinClassFileHeader {
+    protected OldAnnotationHeader(@NotNull FqName fqName) {
+        super(AbiVersionUtil.INVALID_VERSION, fqName);
+    }
+}
diff --git a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/SerializedDataHeader.java b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/SerializedDataHeader.java
new file mode 100644
index 00000000000..6dadf4262a3
--- /dev/null
+++ b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/header/SerializedDataHeader.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2010-2013 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.resolve.java.header;
+
+import com.intellij.openapi.diagnostic.Logger;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.resolve.name.FqName;
+
+import static org.jetbrains.jet.lang.resolve.java.AbiVersionUtil.isAbiVersionCompatible;
+
+public class SerializedDataHeader extends KotlinClassFileHeader {
+    private static final Logger LOG = Logger.getInstance(SerializedDataHeader.class);
+
+    public enum Kind {
+        CLASS,
+        PACKAGE
+    }
+
+    private final String[] data;
+    private final Kind kind;
+
+    private SerializedDataHeader(int version, @Nullable String[] annotationData, @NotNull Kind kind, @NotNull FqName fqName) {
+        super(version, fqName);
+        this.data = annotationData;
+        this.kind = kind;
+    }
+
+    @Nullable
+    public static SerializedDataHeader create(int version, @Nullable String[] annotationData, @NotNull Kind kind, @NotNull FqName fqName) {
+        if (isAbiVersionCompatible(version) && annotationData == null) {
+            LOG.error("Kotlin annotation " + kind + " is incorrect for class: " + fqName);
+            return null;
+        }
+        return new SerializedDataHeader(version, annotationData, kind, fqName);
+    }
+
+    @Nullable
+    public String[] getAnnotationData() {
+        return data;
+    }
+
+    @NotNull
+    public Kind getKind() {
+        return kind;
+    }
+}
diff --git a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/resolver/DeserializedDescriptorResolver.java b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/resolver/DeserializedDescriptorResolver.java
index d4888218ee3..a358ed57f18 100644
--- a/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/resolver/DeserializedDescriptorResolver.java
+++ b/core/descriptor.loader.java/src/org/jetbrains/jet/lang/resolve/java/resolver/DeserializedDescriptorResolver.java
@@ -26,6 +26,7 @@ import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
 import org.jetbrains.jet.lang.descriptors.NamespaceDescriptor;
 import org.jetbrains.jet.lang.resolve.java.header.KotlinClassFileHeader;
+import org.jetbrains.jet.lang.resolve.java.header.SerializedDataHeader;
 import org.jetbrains.jet.lang.resolve.lazy.storage.LockBasedStorageManager;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.name.Name;
@@ -34,7 +35,6 @@ import org.jetbrains.jet.lang.resolve.scopes.JetScope;
 import javax.inject.Inject;
 import java.util.Collection;
 
-import static org.jetbrains.jet.lang.resolve.java.AbiVersionUtil.isAbiVersionCompatible;
 import static org.jetbrains.jet.lang.resolve.java.DescriptorSearchRule.IGNORE_KOTLIN_SOURCES;
 import static org.jetbrains.jet.lang.resolve.java.DescriptorSearchRule.INCLUDE_KOTLIN_SOURCES;
 import static org.jetbrains.jet.lang.resolve.java.resolver.DeserializedResolverUtils.kotlinFqNameToJavaFqName;
@@ -127,14 +127,13 @@ public final class DeserializedDescriptorResolver {
     @Nullable
     private String[] readData(@NotNull VirtualFile virtualFile) {
         KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(virtualFile);
-        if (header == null) {
-            return null;
+        if (header instanceof SerializedDataHeader && header.isCompatibleKotlinCompiledFile()) {
+            return ((SerializedDataHeader) header).getAnnotationData();
         }
-        int version = header.getVersion();
-        if (!isAbiVersionCompatible(version)) {
-            errorReporter.reportIncompatibleAbiVersion(header.getFqName(), virtualFile, version);
-            return null;
+
+        if (header != null) {
+            errorReporter.reportIncompatibleAbiVersion(header.getFqName(), virtualFile, header.getVersion());
         }
-        return header.getAnnotationData();
+        return null;
     }
 }
diff --git a/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java b/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
index a6aea3eb93b..df6ae5fa630 100644
--- a/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
+++ b/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
@@ -30,6 +30,7 @@ import org.jetbrains.jet.descriptors.serialization.*;
 import org.jetbrains.jet.lang.descriptors.ClassKind;
 import org.jetbrains.jet.lang.resolve.java.JavaResolverPsiUtils;
 import org.jetbrains.jet.lang.resolve.java.header.KotlinClassFileHeader;
+import org.jetbrains.jet.lang.resolve.java.header.SerializedDataHeader;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.util.QualifiedNamesUtil;
@@ -104,8 +105,8 @@ public class JetFromJavaDescriptorHelper {
         VirtualFile virtualFile = getVirtualFileForPsiClass(psiClass);
         if (virtualFile != null) {
             KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(virtualFile);
-            if (header != null) {
-                String[] data = header.getAnnotationData();
+            if (header instanceof SerializedDataHeader) {
+                String[] data = ((SerializedDataHeader) header).getAnnotationData();
                 if (data != null) {
                     return JavaProtoBufUtil.readClassDataFrom(data);
                 }
@@ -119,8 +120,8 @@ public class JetFromJavaDescriptorHelper {
         VirtualFile virtualFile = getVirtualFileForPsiClass(psiClass);
         if (virtualFile != null) {
             KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(virtualFile);
-            if (header != null) {
-                String[] data = header.getAnnotationData();
+            if (header instanceof SerializedDataHeader) {
+                String[] data = ((SerializedDataHeader) header).getAnnotationData();
                 if (data != null) {
                     return JavaProtoBufUtil.readPackageDataFrom(data);
                 }
diff --git a/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledDataFactory.java b/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledDataFactory.java
index c17c338e8e2..7c52dd19643 100644
--- a/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledDataFactory.java
+++ b/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledDataFactory.java
@@ -28,6 +28,7 @@ import org.jetbrains.jet.lang.resolve.BindingTraceContext;
 import org.jetbrains.jet.lang.resolve.MemberComparator;
 import org.jetbrains.jet.lang.resolve.java.JavaDescriptorResolver;
 import org.jetbrains.jet.lang.resolve.java.header.KotlinClassFileHeader;
+import org.jetbrains.jet.lang.resolve.java.header.SerializedDataHeader;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.renderer.DescriptorRenderer;
 import org.jetbrains.jet.renderer.DescriptorRendererBuilder;
@@ -48,7 +49,7 @@ public final class DecompiledDataFactory {
     @NotNull
     private final JavaDescriptorResolver javaDescriptorResolver;
     @NotNull
-    private final KotlinClassFileHeader kotlinClassFileHeader;
+    private final SerializedDataHeader classFileHeader;
     @NotNull
     private final VirtualFile classFile;
     @NotNull
@@ -62,8 +63,8 @@ public final class DecompiledDataFactory {
         this.javaDescriptorResolver = injector.getJavaDescriptorResolver();
 
         KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(classFile);
-        assert header != null : "Decompiled data factory shouldn't be called on an unsupported file: " + classFile;
-        this.kotlinClassFileHeader = header;
+        assert header instanceof SerializedDataHeader : "Decompiled data factory shouldn't be called on an unsupported file: " + classFile;
+        this.classFileHeader = (SerializedDataHeader) header;
     }
 
     @NotNull
@@ -72,10 +73,10 @@ public final class DecompiledDataFactory {
     }
 
     private JetDecompiledData build() {
-        FqName packageFqName = kotlinClassFileHeader.getFqName().parent();
+        FqName packageFqName = classFileHeader.getFqName().parent();
         appendDecompiledTextAndPackageName(packageFqName);
-        KotlinClassFileHeader.HeaderType type = kotlinClassFileHeader.getType();
-        if (type == KotlinClassFileHeader.HeaderType.PACKAGE) {
+        SerializedDataHeader.Kind kind = classFileHeader.getKind();
+        if (kind == SerializedDataHeader.Kind.PACKAGE) {
             NamespaceDescriptor nd = javaDescriptorResolver.resolveNamespace(packageFqName, INCLUDE_KOTLIN_SOURCES);
             if (nd != null) {
                 for (DeclarationDescriptor member : sortDeclarations(nd.getMemberScope().getAllDescriptors())) {
@@ -88,13 +89,15 @@ public final class DecompiledDataFactory {
                 }
             }
         }
-        else {
-            assert type == KotlinClassFileHeader.HeaderType.CLASS;
-            ClassDescriptor cd = javaDescriptorResolver.resolveClass(kotlinClassFileHeader.getFqName(), INCLUDE_KOTLIN_SOURCES);
+        else if (kind == SerializedDataHeader.Kind.CLASS) {
+            ClassDescriptor cd = javaDescriptorResolver.resolveClass(classFileHeader.getFqName(), INCLUDE_KOTLIN_SOURCES);
             if (cd != null) {
                 appendDescriptor(cd, "");
             }
         }
+        else {
+            throw new UnsupportedOperationException("Unknown header kind: " + kind);
+        }
 
         JetFile jetFile = JetDummyClassFileViewProvider.createJetFile(PsiManager.getInstance(project), classFile, builder.toString());
         return new JetDecompiledData(jetFile, renderedDescriptorsToRange);
diff --git a/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledUtils.java b/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledUtils.java
index 0cf7234628a..950d079f2a1 100644
--- a/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledUtils.java
+++ b/idea/src/org/jetbrains/jet/plugin/libraries/DecompiledUtils.java
@@ -20,6 +20,7 @@ import com.intellij.openapi.fileTypes.StdFileTypes;
 import com.intellij.openapi.vfs.VirtualFile;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.resolve.java.header.KotlinClassFileHeader;
+import org.jetbrains.jet.lang.resolve.java.header.SerializedDataHeader;
 
 public final class DecompiledUtils {
 
@@ -29,7 +30,7 @@ public final class DecompiledUtils {
         }
         //TODO: check index
         KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(file);
-        return header != null && header.isCompatibleKotlinCompiledFile();
+        return header instanceof SerializedDataHeader && header.isCompatibleKotlinCompiledFile();
     }
 
     private DecompiledUtils() {
diff --git a/idea/src/org/jetbrains/jet/plugin/vfilefinder/KotlinClassFileIndex.java b/idea/src/org/jetbrains/jet/plugin/vfilefinder/KotlinClassFileIndex.java
index ee5435d884d..0485176d125 100644
--- a/idea/src/org/jetbrains/jet/plugin/vfilefinder/KotlinClassFileIndex.java
+++ b/idea/src/org/jetbrains/jet/plugin/vfilefinder/KotlinClassFileIndex.java
@@ -7,6 +7,7 @@ import com.intellij.util.indexing.*;
 import com.intellij.util.io.KeyDescriptor;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.resolve.java.header.KotlinClassFileHeader;
+import org.jetbrains.jet.lang.resolve.java.header.SerializedDataHeader;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 
 import java.io.DataInput;
@@ -58,7 +59,7 @@ public final class KotlinClassFileIndex extends ScalarIndexExtension<FqName> {
         public Map<FqName, Void> map(FileContent inputData) {
             try {
                 KotlinClassFileHeader header = KotlinClassFileHeader.readKotlinHeaderFromClassFile(inputData.getFile());
-                if (header != null && header.isCompatibleKotlinCompiledFile()) {
+                if (header instanceof SerializedDataHeader && header.isCompatibleKotlinCompiledFile()) {
                     return Collections.singletonMap(header.getFqName(), null);
                 }
             }