I started my APM journey when using Spring w/ Java and fell in love with how i can trace the entire flow through the entire application and then just config on

I started my APM journey when using Spring w/ Java and fell in love with how i can trace the entire flow through the entire application and then just config on how many spans i want to send over and what sample rate i want collected. I'd love to accomplish that. What you mentioned is all nice and well (optimal route), but right now, i'm working with some applications that needs it, but has i don't even know how many methods / classes that i'd need to go through and implement it on.