Disclaimer: I work at AWS on an unrelated team. I was not involved in development of this product. Opinions stated are my own, and not necessarily a reflection of my employer. Nothing here is being posted in any sort of official capacity.

There's lots of focus here in the comments on the code reviewer portion, but one of the things I'm most excited about is the profiler - https://aws.amazon.com/codeguru/features/

I do a lot of performance engineering work, and one of my go to tools for visualizing where programs are spending their time is flamegraphs. While you can certainly create them with profilers besides CodeGuru (and I do not work with Java, so I haven't yet had the chance to check out CodeGuru for any of my use cases), I'm super excited about anything that gets more people using them. They make it very easy to see where your optimization opportunities are, and I have personally found them very useful when working with our customers - they're way easier, in my opinion, to go through and explain than just looking at raw perf output or similar.

A profiling tool I want to try out—it seems almost magical—is Coz. It can estimate the effect of speeding up any line of code. It does this by pausing (!) other threads, so it gives a 'virtual' speed up for that line.

What's interesting is that this technique correctly handles inter-thread effects like blocking, locking, contention, so it can point out inter-thread issues that traditional profilers and flame graphs struggle with.

Summary: https://blog.acolyer.org/2015/10/14/coz-finding-code-that-co...

Video presentation: https://www.youtube.com/watch?v=jE0V-p1odPg&t=0m28s

Coz: https://github.com/plasma-umass/coz

JCoz (Java version): http://decave.github.io/JCoz/ and https://github.com/Decave/JCoz