Google Cloud Dataflow BigQueryIO.Read空指针错误

I have a streaming job in which I'm listening to message from PubSub and after that reading the data from BigQuery. Data has is queried using the data received from PubSUb. This means I need to form the query dynamically and then pass it to the BigQueryIO.Read.fromQuery() function. Below is the code which is going to read data from the BigQuery and return a TableRow, but it is giving me NullPointerException where my code is executing data to read.I have a streaming job in which I'm listening t