Seems like an interesting effort. A developer is building an alternative Java-based backend to Lemmy’s Rust-based one, with the goal of building in a handful of different features. The dev is looking at using this compatibility to migrate their instance over to the new platform, while allowing the community to use their apps of choice.
That is true, I used to be an Android developer and then learned Rust by writing code for Lemmy. Are you by any chance my new stalker?
And if we’re comparing the languages, the fact alone that there are no Nullpointerexceptions makes Rust infinitely better than Java for me. I also agree that this sort of copycat project will soon be forgotten. For example have you ever heard of Rustodon?
No, it was on that AMA you guys did months ago, and I remember things about people.
Very impressive! The only thing I can remember well are places.
what’s wrong with having null pointer exception?
Null is terrible.
A lot of languages have it available as a valid return value for most things, implicitly. This also means you have to do extra checking or something like this will blow up with an exception:
// java example // can throw exception String address = person.getAddress().toUpperCase(); // safe String address = ""; if (person.getAddress() != null) { person.getAddress().toUpperCase(); }There are a ton of solutions out there. Many languages have added null-coalescing and null-conditional operators – which are a shorthand for things like the above solutions. Some languages have removed the implicit nulls (like Kotlin), requiring them to be explicitly marked in their type. Some languages have a wrapper around nullable values, an Option type. Some languages remove null entirely from the language (I believe Rust falls into this, using an option type in place of).
Not having null isn’t particularly common yet, and isn’t something languages can just change due to breaking backwards compatibility. However, languages have been adding features over time to make nulls less painful, and most have some subset of the above as options to help.
I do think Option types are fantastic solutions, making you deal with the issue that a none/empty type can exist in a particular place. Java has had them for basically 10 years now (since Java 8).
// optional example Class Person { private String address; //prefer this if a null could ever be returned public Optional<String> getAddress() { return Optional.ofNullable(address); } // not this public String getAddress() { return address; }When consuming, it makes you have to handle the null case, which you can do a variety of ways.
// set a default String address = person.getAddress().orElse("default value"); // explicitly throw an exception instead of an implicit NullPointerException as before String address = person.getAddress().orElseThrow(SomeException::new); // use in a closure only if it exists person.getAddress().ifPresent(addr -> logger.debug("Address {}", addr)); // first example, map to modify, and returning default if no value String address = person.getAddress().map(String::toUpperCase).orElse("");