When online checking is specified, SQLJ will connect to a specified database schema to verify that the database supports all the database tables, stored procedures, and SQL syntax that the application uses. It also verifies that the host variable types in the SQLJ application are compatible with data types of corresponding database columns.

For Oracle$-$specific SQLJ code generation $(-$codegen$=$oracle, which is default$).$ SQL operations are converted directly into Oracle JDBC calls.