Java Web App的CPU消耗率很高

I'm new here and I'm not that very good in CPU consumption and Multi Threading. But I was wondering why my web app is consuming too much of the CPU process? What my program does is update values in the background so that users don't have to wait for the processing of the data and will only need to fetch it upon request. The updating processes are scheduled tasks using executor library that fires off 8 threads every 5 seconds to update my data.I'm new here and I'm not that very good in CPU