Javalin 1 to 2 migration guide

Package structure

Javalin 2 has some changes to the package structure:

• io.javalin.embeddedserver.jetty.websocket -> io.javalin.websocket
• io.javalin.embeddedserver.Location -> io.javalin.staticfiles.Location
• io.javalin.translator.json.JavalinJsonPlugin -> io.javalin.json.JavalinJson
• io.javalin.translator.json.JavalinJacksonPlugin -> io.javalin.json.JavalinJackson
• io.javalin.translator.template.JavalinXyzPlugin -> io.javalin.rendering.JavalinXyz
• io.javalin.security.Role.roles -> io.javalin.security.SecurityUtil.roles
• io.javalin.ApiBuilder -> io.javalin.apibuilder.ApiBuilder
• io.javalin.ApiBuilder.EndpointGrooup -> io.javalin.apibuilder.EndpointGrooup

Server customization/defaults

app.embeddedServer(new EmbeddedJettyFactory(() -> new Server())) // v1
app.server(() -> new Server()) // v2

• The static method Javalin.start(port) has been removed. Javalin.create().start(0); is now required.
• Dynamic gzip is now enabled by default, turn it off with disableDynamicGzip()
• Request-caching is now limited to 4kb by default
• Server now has a LowResourceMonitor attached by default
• defaultCharset() method has been removed
• URLs are now case-insensitive by default, meaning Javalin will treat /path and /Path as the same URL. This can be disabled with app.enableCaseSensitiveUrls().

WebSockets

It was possible to defined WebSockets using Jetty annotations in v1 of Javalin. These Jetty WebSockets have limited functionality compared to the Javalin lambda WebSockets, which is why they have been removed.

AccessManager

• Use Set instead of List
• The AccessManager now runs for every single request, but the default-implementation does nothing. This might break some implementations that relied on un-managed routes.

Context

• The CookieBuilder class has been removed, use Cookie directly.
• ctx.uri() has been removed, it was a duplicate of ctx.path()
• Things that used to return Array<T> now return List<T>
• Things that used to return nullable collections now return empty collections instead
• ctx.param() is now ctx.pathParam()
• ctx.xyzOrDefault("key") methods have been change into ctx.xyz("key", "default")
• ctx.next() has been removed
• Kotlin users can now do ctx.body<MyClass>() to deserialize json
• ctx.request() is now ctx.req
• ctx.response() is now ctx.res
• All ctx.renderXyz methods are now just ctx.render() (correct engine is chosen based on extension)
• ctx.charset(charset) has been removed

Events

• Event handlers no longer take Event as an argument (they now take nothing)
• io.javalin.event.EventType is now io.javalin.JavalinEvent

Misc

• Reverse routing has been removed (will come back, but better)
• HaltException has been removed and replaced with HttpResponseException. Some common responses are included:
  • RedirectResponse
  • BadRequestResponse
  • UnauthorizedResponse
  • ForbiddenResponse
  • NotFoundResponse
  • MethodNotAllowedResponse
  • InternalServerErrorResponse
  • ServiceUnavailableResponse