Fix NPE that could occur when closing a complex query that hasn't been fully initialized

Author: gmfeinberg

CHANGELOG.md

@@ -22,6 +22,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).
 - Authentication calls for on premises login will now honor the request timeout
   rather than using a hard-coded 30s timeout
 
+### Fixed
+- Fixed a problem where if QueryRequest were created with a complex query and
+  closed before results were handled a null pointer exception could occur.
+
 ## [5.4.17] 2025-03-03
 
 ### Added

driver/src/main/java/oracle/nosql/driver/query/QueryDriver.java

@@ -234,14 +234,17 @@ private void setQueryResult(QueryResult result) {
     }
 
     public void close() {
-        theRequest.getPreparedStatement().driverPlan().close(theRCB);
+        /* if there is no RCB there is no state to clean up */
+        if (theRCB != null) {
+            theRequest.getPreparedStatement().driverPlan().close(theRCB);
+        }
         if (theResults != null) {
             theResults.clear();
             theResults = null;
         }
     }
 
     public String getQueryTrace() {
-        return theRCB.getQueryTrace();
+        return theRCB != null ? theRCB.getQueryTrace() : null;
     }
 }