The TIOBE Index for January, 2016 has Java at number one. Rust is at 47 and Go is outside the top 50:
http://spectrum.ieee.org/static/interactive-the-top-programm...
You can break it down by classes of development (web, mobile, enterprise, embedded) as well as weighting (Spectrum, trending, jobs, open, custom). Spectrum's index (even though it's from 2014 and includes things TIOBE doesn't like SQL) isn't so very different from TIOBE's index.
"In order to filter out false positives, two mechanisms are used. First of all a confidence is defined for a language. By default the confidence is 100%, but for some difficult search queries such as "Basic Programming", the confidence will be lower. Apart from the confidence, sometimes also exceptions or mandatory additions are used to weed out false positives."
What they do is that add the term "+Google" to the search terms, yet for the other incredibly popular word "Rust", they don't add "+Mozilla". TIOBE is laughable.
Its based on search engine 'search' text typed by users. 'Go' and 'Rust' are both words used for a wide variety of purposes apart from programming languages. Same with Python.
Don't trust TIOBE on these things.