[lmilcin]

On one of the projects I had trouble convincing the company to stay on Java for their application when they were displeased with the performance.

The previous developers were just careless/clueless about performance and when it started becoming a problem they cited good patterns they were following and blamed Java for their problems. The tech lead wanted to rewrite it in C++ which would be suicide IMO.

What I did, I created a graph in a form of horizontal bar which showed color-coded parts of transaction processing. The color codes showed different parts: business logic, frameworks, infrastructure, communication, etc. I then marked a different graph showing which parts of this was unnecessary with some notes of how this can be optimized. You guess, the parts that were not easily optimized away were very hard to find.

In the end we stayed on Java achieving almost two orders of magnitude performance improvement.