Default port or not?

Javalin has used port 7000 since v1 in case no port is specified. I recently changed this to port 0, which means Javalin will start on a random available port in case you don’t specify a port explicitly.

Javalin.create().start(); // before, this would start on port 7000

Any thoughts on this change?

[pkkummermo]

Randomness is weird, I’d rather have a default port. Default ports has a tendency to be remembered in browsers when debugging as well 😃

[tipsy]

I searched for javalin start on GitHub and have looked through about a hundred of the projects at random. I didn’t find a single one that calls start() without a port specified, unless it was using a custom Server.

(There are some projects that call start() without a port, but they use an older version of Javalin where you had to call port(port).start())

I could of course have gotten lucky with my samples, but I’m starting to think this won’t be a very dramatic change. A lot of projects changed it to 8080 too.

What do you think of making the start function fun start(port: Int?). Just don’t have a default. Have both null and 0 bind to a random port.

I would really liket that, but we have to support the case where you’re starting a Server that has its own custom connectors. It could be possible to change server from being a config option to being an overload on start, so you have

start(port)
start(port, host)
start(server)

But that comes with its own set of challenges (we need to be careful to not introduce a hard dependency on Jetty).