[github-709] Make BitFieldFactory threadsafe. Thanks to ZhangChen. This

closes #709 git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1921332 13f79535-47bb-0310-9956-ffa450edef68
apache · Oct 15, 2024 · ab68210 · ab68210
1 parent f8bbec3
commit ab68210
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/poi/src/main/java/org/apache/poi/util/BitFieldFactory.java b/poi/src/main/java/org/apache/poi/util/BitFieldFactory.java
@@ -18,13 +18,13 @@ Licensed to the Apache Software Foundation (ASF) under one or more
 
 package org.apache.poi.util;
 
-import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Returns immutable Bitfield instances.
  */
 public class BitFieldFactory {
-    private static Map<Integer, BitField> instances = new HashMap<>();
+    private static final ConcurrentHashMap<Integer, BitField> instances = new ConcurrentHashMap<>();
 
     public static BitField getInstance(int mask) {
         return instances.computeIfAbsent(mask, k -> new BitField(mask));