Minimal web servers in scala, supporting a simple GET / HEAD endpoint

http4s.scala

import $ivy.`org.http4s::http4s-dsl:0.18.13`
import $ivy.`org.http4s::http4s-blaze-server:0.18.13`

import cats.effect._
import org.http4s._
import org.http4s.dsl.io._
import org.http4s.server.blaze._

val response = "This is the response"
val port = 8000
val service = HttpService[IO] {
  case  GET -> Root / "test" ⇒ Ok(response)
  case HEAD -> Root / "test" ⇒ Ok(response)
}

val builder =
  BlazeBuilder[IO]
    .bindHttp(port, "localhost")
    .mountService(service, "/")
    .start

val server = builder.unsafeRunSync()
server.shutdown.unsafeRunSync()

java.scala

import java.net.InetSocketAddress
import com.sun.net.httpserver.{ HttpExchange, HttpHandler, HttpServer }

val response = "This is the response"

class MyHandler
  extends HttpHandler {
  def handle(t: HttpExchange): Unit = {
    if (t.getRequestMethod == "GET") {
      t.sendResponseHeaders(200, response.length)
      val os = t.getResponseBody
      os.write(response.getBytes)
      os.close()
    } else if (t.getRequestMethod == "HEAD") {
      t.getResponseHeaders.add("Content-Length", response.length.toString)
      t.sendResponseHeaders(200, -1)
    }
  }
}

val port = 8000
val server: HttpServer = HttpServer.create(new InetSocketAddress(port), 0)
server.createContext("/test", new MyHandler)
server.setExecutor(null)
server.start()
server.stop(0)