The CPU utilization is going to 100% regularly, and when I check SP\_who2, it is showing around 20000 sessions, most of them are sleeping (also utilizing the CPU).  

I think the CPU load is related to the sleeping sessions

The application name is showing as Microsoft JDBC. 

Most of the sessions are showing 'SOS\_SCHEDULER\_YIELD as last\_wait\_type. After restarting the Windows Server, the CPU utilzation has come down, but the session count is increasing. 

The server has 32 cores.

The application team is telling they are using some 'Connection Pool' for the the connection management. 

How can I investigate or solve the number of sleeping sessions?