@Repository
public class MyClass{
    @Autowired
    NamedParameterJdbcTemplate jdbcTemplate;
    public void myMethod(){
        try{
            //OracleDataSource ods = new OracleDataSource();                                           // This works but is obviously not Spring
            OracleDataSource ods = (OracleDataSource) jdbcTemplate.getJdbcTemplate().getDataSource();   // This fails
            ods.setURL(url);
            ods.setUser(user);
            ods.setPassword(pass);
            // ...
        }
        catch(Exception e){
            System.out.println("In Exception");
            e.printStackTrace();
        }
    }
}

spring.datasource.url=jdbc:oracle:thin:@//${ORA_HOST}:${ORA_PORT}/${ORA_SID}
spring.datasource.username=${USER}
spring.datasource.password=${PASS}

In Exception
java.lang.ClassCastException: com.zaxxer.hikari.HikariDataSource cannot be cast to oracle.jdbc.pool.OracleDataSource

Connection conn = this.jdbcTemplate.getJdbcTemplate().getDataSource().getConnection().unwrap(OracleConnection.class);