Webasm

these days almost everyone uses JavaScript and not job in the browser. You could use a tool kit like GWT to do cross compilation but this comes with some significant downsides. So generally speaking if you're using Java and your back and you usually use JavaScript in your front end. in practice this eliminates shared code which is often necessary to do things like validation. it is often difficult to have two copies of the same code written in different languages, and in practice probably by different people, maintained identical functionality as changes are made over time. so this gives rise not only to wasted time and effort but also potentially to security vulnerabilities, an area where JavaScript is already not great.

Rust can execute through something called Web assembly. This means programs written in Rust can safely run in the browser without any special plugin. This allows you to use Rust for both your front-end and back-end code. It also provides your in-browser code with the safety of Rust and the performance of native code. This is a huge win for productivity because it means you can have a single code base with a much higher degree of validation testing.