When comparing Rocket vs Java, the Slant community recommends Rocket for most people. In the question“What are the best backend web frameworks?” Rocket is ranked 14th while Java is ranked 42nd. The most important reason people chose Rocket is:
Rocket makes extensive use of Rust's code generation tools to provide a clean API.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Easy To Use
Rocket makes extensive use of Rust's code generation tools to provide a clean API.
Pro Streams
Rocket streams all incoming and outgoing data, so size isn't a concern.
Pro Cookies
View, add, or remove cookies, with or without encryption, without hassle.
Pro Testing Library
Unit test your applications with ease using the built-in testing library.
Pro Extensible
Easily create your own primitives that any Rocket application can use.
Pro Templating
Rocket makes rendering templates a breeze with built-in templating support.
Pro Query Strings
Handling query strings and parameters is type-safe and easy in Rocket.
Pro Type Safe
From request to response Rocket ensures that your types mean something.
Pro Boilerplate Free
Spend your time writing code that really matters, and let Rocket generate the rest.
Pro Config Environments
Configure your application your way for development, staging, and production.
Pro Verbosity
It makes it easy to debug and to read code.
Pro Mature ecosystem
The language and all its tools have enough time to age and they've aged well.
Pro Type-safe
It is easier to catch errors sooner.
Cons
Con Abandoned
Con Nightly
Uses only nightly versions of Rust.
Con Memory hungry
Running the virtual machine, application server and application itself consumes significant amount of resources.
Con Unnecessarily obtuse and verbose
If you like typing 40 lines of code to open a file, Java is the language for you. If, on the other hand, you’d actually like to get something done, look elsewhere.
Con Oracle
Enough said.
In more detail: Oracle has acquired Java from Sun and continues to surround it with controversy ever since (legendary lawsuit with google, money extortion from the enterprise users etc.).