Checking for null cursorCleaningService in Mongo.close()

   JAVA-1798

Author: jyemin

driver/src/main/com/mongodb/Mongo.java

@@ -469,7 +469,9 @@ public void dropDatabase(final String dbName) {
      */
     public void close() {
         cluster.close();
-        cursorCleaningService.shutdownNow();
+        if (cursorCleaningService != null) {
+            cursorCleaningService.shutdownNow();
+        }
     }
 
     /**

driver/src/test/unit/com/mongodb/MongoConstructorsTest.java

@@ -114,6 +114,12 @@ public void shouldSaveDefaultWriteConcern() throws UnknownHostException {
         }
     }
 
+    @Test
+    public void shouldCloseWithoutExceptionWhenCursorFinalizerIsDisabled() {
+        Mongo mongo = new MongoClient(new ServerAddress(), MongoClientOptions.builder().cursorFinalizerEnabled(false).build());
+        mongo.close();
+    }
+
     @Test
     @SuppressWarnings("deprecation") // This is for testing the old API, so it will use deprecated methods
     public void shouldGetDB() throws UnknownHostException {