diff --git a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/KotlinClassFileHeader.java b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/KotlinClassFileHeader.java
index 16f3bc8e916..490cfc88e87 100644
--- a/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/KotlinClassFileHeader.java
+++ b/compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/resolver/KotlinClassFileHeader.java
@@ -23,18 +23,6 @@ import java.util.List;
 import static org.jetbrains.asm4.ClassReader.*;
 
 public final class KotlinClassFileHeader {
-    @Nullable
-    public static ClassData readClassData(@NotNull VirtualFile virtualFile) {
-        String[] data = readKotlinHeaderFromClassFile(virtualFile).getAnnotationData();
-        return data != null ? JavaProtoBufUtil.readClassDataFrom(data) : null;
-    }
-
-    @Nullable
-    public static PackageData readPackageData(@NotNull VirtualFile virtualFile) {
-        String[] data = readKotlinHeaderFromClassFile(virtualFile).getAnnotationData();
-        return data != null ? JavaProtoBufUtil.readPackageDataFrom(data) : null;
-    }
-
     @NotNull
     public static KotlinClassFileHeader readKotlinHeaderFromClassFile(@NotNull VirtualFile virtualFile) {
         try {
@@ -71,20 +59,51 @@ public final class KotlinClassFileHeader {
 
     @Nullable
     private String[] annotationData = null;
-
     @NotNull
     HeaderType type = HeaderType.NONE;
+    @Nullable
+    JvmClassName jvmClassName = null;
 
     public int getVersion() {
         return version;
     }
 
-    @Nullable
+    @NotNull
+    public HeaderType getType() {
+        return type;
+    }
+
+    public boolean isKotlinCompiledFile() {
+        return type != HeaderType.NONE;
+    }
+
+    @NotNull
+    public JvmClassName getJvmClassName() {
+        assert jvmClassName != null;
+        return jvmClassName;
+    }
+
     public String[] getAnnotationData() {
+        assertDataRead();
+        return annotationData;
+    }
+
+    private void assertDataRead() {
         if (annotationData == null && type != HeaderType.NONE) {
             throw new IllegalStateException("Data for annotations " + type.correspondingAnnotation + " was not read.");
         }
-        return annotationData;
+    }
+
+    @NotNull
+    public ClassData readClassData() {
+        assert type == HeaderType.CLASS;
+        return JavaProtoBufUtil.readClassDataFrom(getAnnotationData());
+    }
+
+    @NotNull
+    public PackageData readPackageData() {
+        assert type == HeaderType.PACKAGE;
+        return JavaProtoBufUtil.readPackageDataFrom(getAnnotationData());
     }
 
     private class ReadDataFromAnnotationVisitor extends ClassVisitor {
@@ -93,6 +112,11 @@ public final class KotlinClassFileHeader {
             super(Opcodes.ASM4);
         }
 
+        @Override
+        public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
+            jvmClassName = JvmClassName.byInternalName(name);
+        }
+
         @Override
         public AnnotationVisitor visitAnnotation(final String desc, boolean visible) {
             for (HeaderType headerType : HeaderType.values()) {
diff --git a/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java b/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
index 39b01015ce0..59cb0c1e830 100644
--- a/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
+++ b/idea/src/org/jetbrains/jet/plugin/caches/JetFromJavaDescriptorHelper.java
@@ -103,14 +103,14 @@ public class JetFromJavaDescriptorHelper {
     private static ClassData getClassData(@NotNull PsiClass psiClass) {
         VirtualFile virtualFile = getVirtualFileForPsiClass(psiClass);
         if (virtualFile == null) return null;
-        return KotlinClassFileHeader.readClassData(virtualFile);
+        return KotlinClassFileHeader.readKotlinHeaderFromClassFile(virtualFile).readClassData();
     }
 
     @Nullable
     private static PackageData getPackageData(@NotNull PsiClass psiClass) {
         VirtualFile virtualFile = getVirtualFileForPsiClass(psiClass);
         if (virtualFile == null) return null;
-        return KotlinClassFileHeader.readPackageData(virtualFile);
+        return KotlinClassFileHeader.readKotlinHeaderFromClassFile(virtualFile).readPackageData();
     }
 
     //TODO: common utility