Rust definitely makes sense anywhere you are currently using C/C++ or Python/Ruby. Java is somewhat of a special case though, especially the Big Data ecosystem

Rust definitely makes sense anywhere you are currently using C/C++ or Python/Ruby. Java is somewhat of a special case though, especially the Big Data ecosystem. Much of the fastest and most important Java tools are written in pure Java (or other JVM language) and as such can't be called from Rust in a reasonable way. Writing Big Data code in Rust is certainly possible from a performance perspective but is an uphill battle of lack of libraries, integration, etc. Some of this might change in time but I don't see Rust ever displacing Java from Big Data. One of the big reasons for this is the main downside of Java is it's GC, which is mainly problematic for latency sensitive applications. In the Big Data field this is substantially reduced as a problem as the code is usually throughput bound and executed outside of interactive contexts, hiding the cost of the GC where it might be more apparent in other applications. I love Rust and I think it has a lot of potential to replace some of the databases and networked services used in data infrastructure, just don't see it displacing Java as the top dog.