fixes #1093

nitrite-rocksdb-adapter/src/main/java/org/dizitart/no2/rocksdb/formatter/NitriteSerializers.java

@@ -9,10 +9,10 @@
 import com.esotericsoftware.kryo.kryo5.serializers.MapSerializer;
 import org.dizitart.no2.collection.Document;
 import org.dizitart.no2.collection.NitriteId;
-import org.dizitart.no2.common.meta.Attributes;
+import org.dizitart.no2.common.DBValue;
 import org.dizitart.no2.common.Fields;
+import org.dizitart.no2.common.meta.Attributes;
 import org.dizitart.no2.common.tuples.Pair;
-import org.dizitart.no2.common.DBValue;
 import org.dizitart.no2.common.util.SpatialKey;
 import org.dizitart.no2.index.BoundingBox;
 import org.dizitart.no2.index.IndexDescriptor;

nitrite-rocksdb-adapter/src/test/java/org/dizitart/no2/NitriteTest.java

@@ -443,6 +443,31 @@ public void run() {
         db.close();
     }
 
+    @Test
+    public void testIssue1093() {
+        ObjectRepository<Receipt> repository = db.getRepository(Receipt.class);
+        repository.clear();
+
+        Receipt receipt1 = new Receipt();
+        receipt1.clientRef = "111-11111";
+        receipt1.status = Receipt.Status.PREPARING;
+
+        Receipt receipt2 = new Receipt();
+        receipt2.clientRef = "222-22222";
+        receipt2.status = Receipt.Status.PREPARING;
+
+        repository = db.getRepository(Receipt.class);
+        repository.update(receipt1, true);
+        repository.update(receipt2, true);
+
+        assertEquals(repository.find().size(), 2);
+        Receipt found1 = repository.getById("111-11111");
+        assertNotNull(found1);
+
+        Receipt found2 = repository.getById("222-22222");
+        assertNotNull(found2);
+    }
+
     @Data
     @AllArgsConstructor
     @NoArgsConstructor

nitrite/src/main/java/org/dizitart/no2/collection/operation/IndexManager.java

@@ -113,6 +113,7 @@ public void clearAll() {
                     String indexMapName = indexMeta.getIndexMap();
                     NitriteMap<?, ?> indexMap = nitriteStore.openMap(indexMapName, Object.class, Object.class);
                     indexMap.clear();
+                    indexMap.close();
                 }
             }
         }

nitrite/src/main/java/org/dizitart/no2/common/DBNull.java

@@ -1,11 +1,14 @@
 package org.dizitart.no2.common;
 
+import lombok.Getter;
+
 /**
  * @author Anindya Chatterjee
  * @since 1.0
  */
 public class DBNull extends DBValue {
     private static final long serialVersionUID = 1598819770L;
+    @Getter
     private static final DBNull instance = new DBNull();
 
     private DBNull() {
@@ -22,10 +25,6 @@ public int compareTo(DBValue o) {
         return -1;
     }
 
-    public static DBNull getInstance() {
-        return instance;
-    }
-
     @Override
     public String toString() {
         return null;