diff --git a/platform/core-impl/src/com/intellij/psi/impl/source/DummyHolder.java b/platform/core-impl/src/com/intellij/psi/impl/source/DummyHolder.java
index 02ff264bfdf5..4bd9b53cb2c1 100644
--- a/platform/core-impl/src/com/intellij/psi/impl/source/DummyHolder.java
+++ b/platform/core-impl/src/com/intellij/psi/impl/source/DummyHolder.java
@@ -31,7 +31,8 @@ public class DummyHolder extends PsiFileImpl {
   private final Boolean myExplicitlyValid;
   private final Language myLanguage;
   private volatile FileElement myFileElement = null;
-  private final Object myTreeElementLock = new String("DummyHolder's tree element lock");
+  @SuppressWarnings("EmptyClass") private static class DummyHolderTreeLock {}
+  private final DummyHolderTreeLock myTreeElementLock = new DummyHolderTreeLock();
 
   public DummyHolder(@NotNull PsiManager manager, TreeElement contentElement, PsiElement context) {
     this(manager, contentElement, context, SharedImplUtil.findCharTableByTree(contentElement));