PR feedback

Author: goekay

src/main/java/de/rwth/idsg/steve/ocpp/ws/SessionContextStoreImpl.java

@@ -142,7 +142,11 @@ public void closeSessions(String chargeBoxId) {
             if (endpointDeque == null) {
                 return;
             }
-            for (SessionContext sessionContext : endpointDeque) {
+
+            // To prevent a ConcurrentModificationException, iterate over a copy of
+            // endpointDeque when closing sessions. The close() operation can trigger an event
+            // that modifies the deque, causing an error.
+            for (SessionContext sessionContext : new ArrayDeque<>(endpointDeque)) {
                 try {
                     sessionContext.getSession().close();
                 } catch (IOException e) {