many JDBC Thin Client connections

We're running a 12.2 environment on many nodes (6), and we are seeing lots of database connections being reported. Detailing into them show this kind of information:

SQL> select count(*),PROGRAM   from  gv$session    group by PROGRAM,MACHINE     order by 1 asc ;

　

  COUNT(*) PROGRAM                                      

---------- ------------------------------------------------

(..)

      1201 JDBC Thin Client                                

      1420 JDBC Thin Client                                

      1531 JDBC Thin Client                                

      1885 JDBC Thin Client                               

(..)

I've left out all details on these messages, but the servers these are reported on, are all and only all of the WLS webservers.

The numbers don't add up; we have some hundred users at peak usage, but not the 5000 to 6000 that is calculated from this information.