nit

Author: Neenu1995

java-bigquery/google-cloud-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryJsonResultSet.java

@@ -290,9 +290,11 @@ private FieldValue getObjectInternal(int columnIndex) throws SQLException {
   @Override
   public void close() throws SQLException {
     LOG.finest("++enter++");
+    if (isClosed()) {
+      return;
+    }
     try (BigQueryJdbcMdc.MdcCloseable mdc =
         BigQueryJdbcMdc.registerInstance(this.statement.connection, this.statement.connectionId)) {
-      checkClosed();
       LOG.fine("Closing BigqueryJsonResultSet %s.", this);
       this.isClosed = true;
       if (ownedThreads != null) {

java-bigquery/google-cloud-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryResultSetMetadata.java

@@ -43,7 +43,7 @@ private BigQueryResultSetMetadata(FieldList schemaFieldList, Statement statement
     this.schemaFieldList = schemaFieldList;
     this.columnCount = schemaFieldList.size();
     this.statement = statement;
-    this.connection = (BigQueryConnection) statement.getConnection();
+    this.connection = statement.getConnection().unwrap(BigQueryConnection.class);
   }
 
   static BigQueryResultSetMetadata of(FieldList schemaFieldList, Statement statement)

java-bigquery/google-cloud-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryStatement.java

@@ -295,7 +295,7 @@ public int executeUpdate(String sql) throws SQLException {
     try (BigQueryJdbcMdc.MdcCloseable mdc =
         BigQueryJdbcMdc.registerInstance(this.connection, this.connectionId)) {
       LOG.finest("++enter++");
-      return checkUpdateCount(executeLargeUpdate(sql));
+      return checkUpdateCount(executeLargeUpdateImpl(sql));
     }
   }