fix

Author: wernerdv

modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/IgniteDhtPartitionHistorySuppliersMap.java

@@ -95,13 +95,7 @@ public synchronized void put(UUID nodeId, int grpId, int partId, long cntr) {
         if (map == null)
             map = new HashMap<>();
 
-        PartitionReservationsMap nodeMap = map.get(nodeId);
-
-        if (nodeMap == null) {
-            nodeMap = new PartitionReservationsMap(new HashMap<>());
-
-            map.put(nodeId, nodeMap);
-        }
+        PartitionReservationsMap nodeMap = map.computeIfAbsent(nodeId, k -> new PartitionReservationsMap());
 
         nodeMap.put(new GroupPartitionIdPair(grpId, partId), cntr);
     }

modules/core/src/main/java/org/apache/ignite/internal/processors/cache/distributed/dht/preloader/PartitionReservationsMap.java

@@ -32,18 +32,6 @@ public class PartitionReservationsMap implements Message {
     @Order(0)
     private Map<GroupPartitionIdPair, Long> map;
 
-    /** Default constructor. */
-    public PartitionReservationsMap() {
-        // No-op.
-    }
-
-    /**
-     * @param map Map.
-     */
-    public PartitionReservationsMap(Map<GroupPartitionIdPair, Long> map) {
-        this.map = map;
-    }
-
     /**
      * @return Map.
      */