ARROW-7199: [Java] Fix ConcurrentModificationException in BaseAllocat…

…or::getChildAllocators synchronize on childAllocators map when iterating on its entries using keySet/entrySet views Closes apache#5856 from pprudhvi/sync-basealloc and squashes the following commits: 052dd83 <Prudhvi Porandla> synchronise over childallocators while iterating on keyset view Authored-by: Prudhvi Porandla <[email protected]> Signed-off-by: Krisztián Szűcs <[email protected]>
tvamsikalyan · Nov 18, 2019 · ec50473 · ec50473
1 parent 1e3545d
commit ec50473
Showing 1 changed file with 7 additions and 3 deletions.
diff --git a/java/memory/src/main/java/org/apache/arrow/memory/BaseAllocator.java b/java/memory/src/main/java/org/apache/arrow/memory/BaseAllocator.java
@@ -125,7 +125,9 @@ public BufferAllocator getParentAllocator() {
 
   @Override
   public Collection<BufferAllocator> getChildAllocators() {
-    return new HashSet<>(childAllocators.keySet());
+    synchronized (childAllocators) {
+      return new HashSet<>(childAllocators.keySet());
+    }
   }
 
   private static String createErrorMsg(final BufferAllocator allocator, final int rounded, final int requested) {
@@ -449,8 +451,10 @@ public synchronized void close() {
     } else {
       if (!childAllocators.isEmpty()) {
         outstandingChildAllocators.append("Outstanding child allocators : \n");
-        for (final BaseAllocator childAllocator : childAllocators.keySet()) {
-          outstandingChildAllocators.append(String.format("  %s", childAllocator.toString()));
+        synchronized (childAllocators) {
+          for (final BaseAllocator childAllocator : childAllocators.keySet()) {
+            outstandingChildAllocators.append(String.format("  %s", childAllocator.toString()));
+          }
         }
       }
     }