Building Scala project with and without sbt

• Preparation
• Method
  • With sbt
    • Installing sbt
    • Building project
  • Without sbt

I want to build .scala file.

Preparation

This post assumes configurations in this earlier post.

Method

With sbt

Installing sbt

sbt stands for Simple Build Tool and is Scala’s de facto build tool.

1. Install sbt from here.
2. Create system variable SBT_HOME and set it to the path of the sbt installation.
3. Add %SBT_HOME%\bin to path.
4. Open cmd and type sbt. Wait for everything to install and the interactive mode with sbt:scala> to pop up.

Building project

1. Create a .scala file containing, say, the following code.

    object Hi{
    def main(args: Array[String]) = println("Hello world!")
    }
   

2. Open cmd, cd to the directory containing the .scala file, and type sbt.
3. Type run. The output should look something like this:

    C:\Users\steve-rogers\scala>sbt
    [warn] Neither build.sbt nor a 'project' directory in the current directory: C:\Users\steve-rogers\scala
    c) continue
    q) quit
    ? c
    Java HotSpot(TM) Client VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
    [warn] No sbt.version set in project/build.properties, base directory: C:\Users\steve-rogers\scala
    [info] Set current project to scala (in build file:/C:/Users/steve-rogers/scala/)
    [info] sbt server started at local:sbt-server-62d2810ebd461b523e48
    sbt:scala> run
    [info] Updating ...
    [info] Done updating.
    [info] Compiling 1 Scala source to C:\Users\steve-rogers\scala\target\scala-2.12\classes ...
    [info] Done compiling.
    [info] Packaging C:\Users\steve-rogers\scala\target\scala-2.12\scala_2.12-0.1.0-SNAPSHOT.jar ...
    [info] Done packaging.
    [info] Running Hi
    Hello world!
    [success] Total time: 5 s, completed Jul 31, 2019 11:28:17 PM
    sbt:scala>
   

Without sbt

1. Create a .scala file containing, say, the following code.

    object Hi{
    def main(args: Array[String]) = println("Hello world!")
    }
   

2. Open cmd, cd to the directory containing the .scala file, and type scalac hello.scala.
3. Observe that the files Hi$.class and Hi.class are created. The latter is what we need to execute. Type scala Hi. The output should look something like this:

    C:\Users\steve-rogers\scala>scala Hi
    Hello world!