Time taken by all the methods used in my application?

I have been given with library called xyz.jar, which performs certain job.This jar has many other methods too.All these methods are used at various places in our applications.This library has exposed some interfaces to client. If I want to print the time taken by all the methods used in my application what should i do??

Calculating time for individual methods is easy but to to calculate the time of execution of all methods what approach should i follow?