How to extract values from database and store in context variables using tdbinput in talend

Question

I have a tdbinput which uses a select query like "select A,B,C from test"

I am trying to store the extracted values per each iteration from the database table into a context variable so i can use it later using tjava or tjavarow.

But when i try to use tdbinput->tjava it fails

My tjava has: context.Atest=input_row.A;

What is the correct way to extract and store in context for each row in the database