From 8762fb8a4d75fa9ab4881649cddc7ab22685263c Mon Sep 17 00:00:00 2001
From: "Anna.Kozlova" <anna.kozlova@jetbrains.com>
Date: Thu, 27 Apr 2017 17:41:18 +0200
Subject: [PATCH] sync instead of concurrent set

---
 .../reference/RefClassImpl.java               | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/reference/RefClassImpl.java b/java/java-analysis-impl/src/com/intellij/codeInspection/reference/RefClassImpl.java
index d8b9b676201d..1b133b4f1c9c 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/reference/RefClassImpl.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/reference/RefClassImpl.java
@@ -58,7 +58,7 @@ public class RefClassImpl extends RefJavaElementImpl implements RefClass {
   private static final int IS_LOCAL_MASK     = 0x1000000;
 
   private Set<RefClass> myBases; // singleton (to conserve the memory) or THashSet
-  private volatile Set<RefClass> mySubClasses;
+  private Set<RefClass> mySubClasses; // singleton (to conserve the memory) or THashSet
   private List<RefMethod> myConstructors;
   private RefMethodImpl myDefaultConstructor;
   private List<RefMethod> myOverridingMethods;
@@ -334,21 +334,30 @@ public class RefClassImpl extends RefJavaElementImpl implements RefClass {
 
   @Override
   @NotNull
-  public Set<RefClass> getSubClasses() {
+  public synchronized Set<RefClass> getSubClasses() {
     if (mySubClasses == null) return EMPTY_CLASS_SET;
     return mySubClasses;
   }
 
-  private void addSubClass(@NotNull RefClass refClass){
+  private synchronized void addSubClass(@NotNull RefClass refClass){
     if (mySubClasses == null) {
-      mySubClasses = ContainerUtil.newConcurrentSet();
+      mySubClasses = Collections.singleton(refClass);
+      return;
+    }
+    if (mySubClasses.size() == 1) {
+      // convert from singleton
+      mySubClasses = new THashSet<>(mySubClasses);
     }
     mySubClasses.add(refClass);
   }
-
-  private void removeSubClass(RefClass refClass){
+  private synchronized void removeSubClass(RefClass refClass){
     if (mySubClasses == null) return;
-    mySubClasses.remove(refClass);
+    if (mySubClasses.size() == 1) {
+      mySubClasses = null;
+    }
+    else {
+      mySubClasses.remove(refClass);
+    }
   }
 
   @Override