Application leading slowness

The apps team when starts JBOSS application it gradually slows down they put a debug and got to know that the queries taking more time in application as compared to when executed in the SQL tool.

I check the exceution plan and the cost is absolutely fine and less to the plan which is getting picked up by running same sql with literals when they run in another tool.

In the tool the plan is doing index skip scan but here this is index range scan in application and index range scan is givging less cost.

Is there a way that I can conmfirm that quesries are taking this much time only in the database rest are the issues with appplication only .I can't put trace on a particular session since this is an application and will be run in differnet sessions