diff --git a/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt b/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
index 542163392a0..d92d0d119e3 100644
--- a/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
+++ b/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/IncrementalCacheImpl.kt
@@ -601,10 +601,7 @@ public class IncrementalCacheImpl(
         override fun dumpValue(value: Boolean) = ""
     }
 
-    private inner class SourceToClassesMap(storageFile: File) : BasicStringMap<List<String>>(storageFile, StringListExternalizer) {
-        override val keyDescriptor: KeyDescriptor<String>
-            get() = PathStringDescriptor.INSTANCE
-
+    private inner class SourceToClassesMap(storageFile: File) : BasicStringMap<List<String>>(storageFile, PathStringDescriptor.INSTANCE, StringListExternalizer) {
         public fun clearOutputsForSource(sourceFile: File) {
             storage.remove(sourceFile.getAbsolutePath())
         }
@@ -676,10 +673,7 @@ public class IncrementalCacheImpl(
      *  * inlineFunction - jvmSignature of some inline function in source file
      *  * target files - collection of files inlineFunction has been inlined to
      */
-    private inner class InlineFunctionsFilesMap(storageFile: File) : BasicMap<PathFunctionPair, Collection<String>>(storageFile, PathCollectionExternalizer) {
-        override val keyDescriptor: KeyDescriptor<PathFunctionPair>
-            get() = PathFunctionPairKeyDescriptor
-
+    private inner class InlineFunctionsFilesMap(storageFile: File) : BasicMap<PathFunctionPair, Collection<String>>(storageFile, PathFunctionPairKeyDescriptor, PathCollectionExternalizer) {
         public fun add(sourcePath: String, jvmSignature: String, targetPath: String) {
             val key = PathFunctionPair(sourcePath, jvmSignature)
             storage.appendData(key) { out ->
diff --git a/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/storage/BasicMap.kt b/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/storage/BasicMap.kt
index db5e3f503d2..c89fb8bc5ce 100644
--- a/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/storage/BasicMap.kt
+++ b/jps-plugin/src/org/jetbrains/kotlin/jps/incremental/storage/BasicMap.kt
@@ -27,10 +27,9 @@ import java.io.IOException
 
 public abstract class BasicMap<K : Comparable<K>, V>(
         private val storageFile: File,
+        private val keyDescriptor: KeyDescriptor<K>,
         private val valueExternalizer: DataExternalizer<V>
 ) {
-    protected abstract val keyDescriptor: KeyDescriptor<K>
-
     protected var storage: PersistentHashMap<K, V> = createMap()
 
     public fun contains(key: K): Boolean = storage.containsMapping(key)
@@ -92,10 +91,13 @@ public abstract class BasicMap<K : Comparable<K>, V>(
 
 public abstract class BasicStringMap<V>(
         storageFile: File,
+        keyDescriptor: KeyDescriptor<String>,
         valueExternalizer: DataExternalizer<V>
-) : BasicMap<String, V>(storageFile, valueExternalizer) {
-    override val keyDescriptor: KeyDescriptor<String>
-        get() = EnumeratorStringDescriptor()
+) : BasicMap<String, V>(storageFile, keyDescriptor, valueExternalizer) {
+    public constructor(
+            storageFile: File,
+            valueExternalizer: DataExternalizer<V>
+    ) : this(storageFile, EnumeratorStringDescriptor.INSTANCE, valueExternalizer)
 
     override fun dumpKey(key: String): String = key
 }
\ No newline at end of file