I was trying to connect to database using the following URL : jdbc:oracle:thin:@//dbs03.~~~~.ca:1521/database_name_dev while JDBC needs an SID to connect to and not a database name or TSN name. Not sure how should you find it out what an SID is for a given database for now, but after changing it to jdbc:oracle:thin:@//dbs03.~~~~.ca:1521/db03, I could connect to database.