akka / akka-quickstart-java.g8

A minimal seed template for an Akka in Java

Akka Quickstart with Java

Quickstart guide

This example is described in the Akka Quickstart with Java guide

The Hello World example illustrates Akka basics. Within 30 minutes, you should be able to download and run the example and use this guide to understand how the example is constructed. This will get your feet wet, and hopefully inspire you to dive deeper into the wonderful sea of Akka!

Giter8 template

It can also be used as a Giter8 template for Akka with Java.

Prerequisites:

• JDK 17
• sbt 1.2.8 or higher (download here)

Open a console and run the following command to apply this template:

sbt new akka/akka-quickstart-java.g8

This template will prompt for the name of the project. Press Enter if the default values suit you.

Once inside the project folder, run the application with:

sbt run

This template also provides build descriptors for maven and gradle. You can use any of the following commands to run the application:

mvn compile exec:exec

or

gradle run

Template license

Written in 2017 by Lightbend, Inc.

To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to this template to the public domain worldwide. This template is distributed without any warranty. See http://creativecommons.org/publicdomain/zero/1.0/.

The Akka family of projects is managed by teams at Lightbend with help from the community.

---

License

Akka is licensed under the Business Source License 1.1, please see the Akka License FAQ.

akka-quickstart-java.g8's Issues

Java documentation talks about using bang method from Scala API

Sorry, I'm not sure where to file this bug. This page: http://developer.lightbend.com/guides/akka-quickstart-java/communicate-with-actors.html says

use the ! (bang) method on the ActorRef

But that's how things are done in Scala, not Java.

build.gradle uses mavenLocal repository

The build.gradle file in this project uses mavenLocal:

repositories {
    mavenLocal()
}

This means that the command gradle run will fail if you haven't already downloaded the necessary akka jars into your .m2 cache. The build.gradle file should use mavenCentral() instead.

attribute akka_version isn't defined

I am running this on a windows 7 machine. What am I doing wrong?

{ t }  » which sbt                                                                                                                                    /d/temp/t
/cygdrive/c/Program Files (x86)/sbt/bin/sbt
{ t }  » java -version                                                                                                                                /d/temp/t
java version "1.8.0_112"
Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)


{ t }  » sbt new akka/akka-java-seed.g8                                                                                                               /d/temp/t
[info] Set current project to t (in build file:/D:/temp/t/)
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

Exiting due to error in the template
File: D:\dev\apps\.babun\cygwin\tmp\giter8-6791571998485\src\main\g8\project\Dependencies.scala, context [anonymous] 4:27 internal error: org.stringtemplate.v4.compiler.STException: context [anonymous] 4:27 attribute akka_version isn't defined
        at giter8.G8$STErrorHandler.runTimeError(g8.scala:110)
        at giter8.G8$STErrorHandler.runTimeError(g8.scala:105)
        at org.stringtemplate.v4.misc.ErrorManager.runTimeError(ErrorManager.java:133)
        at org.stringtemplate.v4.Interpreter._exec(Interpreter.java:193)
        at org.stringtemplate.v4.Interpreter.exec(Interpreter.java:145)
        at org.stringtemplate.v4.ST.write(ST.java:427)
        at org.stringtemplate.v4.ST.render(ST.java:497)
        at org.clapper.scalasti.ST.render(ST.scala:286)
        at giter8.G8$.applyTemplate(g8.scala:102)
        at giter8.G8$.write(g8.scala:154)
        at giter8.G8$.write(g8.scala:138)
        at giter8.G8$$anonfun$writeTemplates$2$$anonfun$apply$11.apply(g8.scala:396)
        at giter8.G8$$anonfun$writeTemplates$2$$anonfun$apply$11.apply(g8.scala:396)
        at scala.util.control.Exception$Catch$$anonfun$opt$1.apply(Exception.scala:118)
        at scala.util.control.Exception$Catch$$anonfun$opt$1.apply(Exception.scala:118)
        at scala.util.control.Exception$Catch.apply(Exception.scala:102)
        at scala.util.control.Exception$Catch.opt(Exception.scala:118)
        at giter8.G8$$anonfun$writeTemplates$2.apply(g8.scala:395)
        at giter8.G8$$anonfun$writeTemplates$2.apply(g8.scala:386)
        at scala.collection.immutable.Stream.foreach(Stream.scala:547)
        at giter8.G8$.writeTemplates(g8.scala:386)
        at giter8.G8$$anonfun$applyT$1.apply(g8.scala:256)
        at giter8.G8$$anonfun$applyT$1.apply(g8.scala:249)
        at scala.util.Either$RightProjection.flatMap(Either.scala:523)
        at giter8.G8$.applyT(g8.scala:249)
        at giter8.G8$.fromDirectory(g8.scala:62)
        at giter8.JgitHelper$$anonfun$run$2.apply(JgitHelper.scala:67)
        at giter8.JgitHelper$$anonfun$run$2.apply(JgitHelper.scala:66)
        at scala.util.Either$RightProjection.flatMap(Either.scala:523)
        at giter8.JgitHelper$.run(JgitHelper.scala:66)
        at giter8.JgitHelper$.run(JgitHelper.scala:78)
        at giter8.Giter8$$anonfun$2.apply(giter8.scala:34)
        at giter8.Giter8$$anonfun$2.apply(giter8.scala:33)
        at scala.Option.map(Option.scala:145)
        at giter8.Giter8.run(giter8.scala:33)
        at sbtgiter8resolver.Giter8TemplateResolver.run(Giter8TemplateResolver.scala:31)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at sbt.TemplateCommandUtil$.call(TemplateCommand.scala:68)
        at sbt.TemplateCommandUtil$.sbt$TemplateCommandUtil$$runTemplate(TemplateCommand.scala:59)
        at sbt.TemplateCommandUtil$$anonfun$2.apply(TemplateCommand.scala:45)
        at sbt.TemplateCommandUtil$$anonfun$2.apply(TemplateCommand.scala:41)
        at scala.collection.LinearSeqOptimized$class.find(LinearSeqOptimized.scala:100)
        at scala.collection.immutable.List.find(List.scala:84)
        at sbt.TemplateCommandUtil$.sbt$TemplateCommandUtil$$run(TemplateCommand.scala:41)
        at sbt.TemplateCommandUtil$$anonfun$templateCommandParser$1.apply(TemplateCommand.scala:34)
        at sbt.TemplateCommandUtil$$anonfun$templateCommandParser$1.apply(TemplateCommand.scala:28)
        at sbt.Command$$anonfun$applyEffect$2$$anonfun$apply$3.apply(Command.scala:61)
        at sbt.Command$$anonfun$applyEffect$2$$anonfun$apply$3.apply(Command.scala:61)
        at sbt.Command$.process(Command.scala:93)
        at sbt.MainLoop$$anonfun$1$$anonfun$apply$1.apply(MainLoop.scala:96)
        at sbt.MainLoop$$anonfun$1$$anonfun$apply$1.apply(MainLoop.scala:96)
        at sbt.State$$anon$1.process(State.scala:184)
        at sbt.MainLoop$$anonfun$1.apply(MainLoop.scala:96)
        at sbt.MainLoop$$anonfun$1.apply(MainLoop.scala:96)
        at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
        at sbt.MainLoop$.next(MainLoop.scala:96)
        at sbt.MainLoop$.run(MainLoop.scala:89)
        at sbt.MainLoop$$anonfun$runWithNewLog$1.apply(MainLoop.scala:68)
        at sbt.MainLoop$$anonfun$runWithNewLog$1.apply(MainLoop.scala:63)
        at sbt.Using.apply(Using.scala:24)
        at sbt.MainLoop$.runWithNewLog(MainLoop.scala:63)
        at sbt.MainLoop$.runAndClearLast(MainLoop.scala:46)
        at sbt.MainLoop$.runLoggedLoop(MainLoop.scala:30)
        at sbt.MainLoop$.runLogged(MainLoop.scala:22)
        at sbt.StandardMain$.runManaged(Main.scala:57)
        at sbt.xMain.run(Main.scala:29)
        at xsbt.boot.Launch$$anonfun$run$1.apply(Launch.scala:109)
        at xsbt.boot.Launch$.withContextLoader(Launch.scala:128)
        at xsbt.boot.Launch$.run(Launch.scala:109)
        at xsbt.boot.Launch$$anonfun$apply$1.apply(Launch.scala:35)
        at xsbt.boot.Launch$.launch(Launch.scala:117)
        at xsbt.boot.Launch$.apply(Launch.scala:18)
        at xsbt.boot.Boot$.runImpl(Boot.scala:41)
        at xsbt.boot.Boot$.main(Boot.scala:17)
        at xsbt.boot.Boot.main(Boot.scala)

Documentation issue on https://developer.lightbend.com/guides/akka-quickstart-java/

Hi all,
Just wanted to submit a few doc issues based on the Quickstart guide.

1. In the console output for Gradle on that page, the type of the Bot should be GreeterBot and not HelloWorldBot.

2. Also on the same page, in the What Hello World does section, the first bullet point should be Greeter and not Greet.

Hope this helps.

Rename this repo to akka-quickstart-java

And make sure to check if all docs are using the new name

Skip Scala version choice

Java users shouldn't need to first select a Scala version, we can hard code that.

The quickstart example is broken on Gradle 7

Following the instructions on this page:

https://developer.lightbend.com/guides/akka-quickstart-java/

Output of gradle run is:

FAILURE: Build failed with an exception.

* Where:
Build file '/mnt/c/Habib/hello-akka/build.gradle' line: 12

* What went wrong:
A problem occurred evaluating root project 'hello-akka'.
> Could not find method compile() for arguments [com.typesafe.akka:akka-actor-typed_2.13:2.6.14] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 9s

Using Gradle 7.0 and Java 11.

Room for improvement:

• Document supported versions of the environment (Gradle, Java)
• Use Gradle wrapper
• Make the build file minimal (remove the idea plugin, and more?)

Edit: Found that it does work on Gradle 6.9. So I have a feeling Akka doesn't work at all on Gradle 7?

Guide shouldn't link to project starter

Per this marketing effort: https://docs.google.com/spreadsheets/d/1IJCclFJYD7SuxdIgYJ9wyHu-rDn-z5Rt-BKWgDOGfz0/edit?usp=sharing Project Starter is going to be removed from Techhub. Instead, the guide should point directly to the download:
https://example.lightbend.com/v1/download/akka-quickstart-java?name=akka-quickstart-java

(re)introduce g8 property for akka version

Use a giter8 maven property perhaps?

Weird comments in Java files

Printer.java has this comment repeated six times:

//#printer-messages

What is this for? Greeter.java is similar.