Setting up sbt

Tried installing with Homebrew. But when you see an error like this, you know you better go read the documentations.

error: error while loading String, class file '/modules/java.base/java/lang/String.class' is broken

The SBT docs say to install with Java 8 or 11. They also recommend using SDKman.

$ sdk list java
	================================================================================
Available Java Versions
================================================================================
 Vendor        | Use | Version      | Dist    | Status     | Identifier
--------------------------------------------------------------------------------
 AdoptOpenJDK  |     | 16.0.0.j9    | adpt    |            | 16.0.0.j9-adpt
               |     | 16.0.0.hs    | adpt    |            | 16.0.0.hs-adpt
               |     | 11.0.10.j9   | adpt    |            | 11.0.10.j9-adpt
               |     | 11.0.10.hs   | adpt    |            | 11.0.10.hs-adpt
               |     | 8.0.282.j9   | adpt    |            | 8.0.282.j9-adpt
               |     | 8.0.282.hs   | adpt    |            | 8.0.282.hs-adpt
 Amazon        |     | 16.0.0.36.1  | amzn    |            | 16.0.0.36.1-amzn
               |     | 15.0.2.7.1   | amzn    |            | 15.0.2.7.1-amzn
               |     | 11.0.10.9.1  | amzn    |            | 11.0.10.9.1-amzn
               |     | 8.282.08.1   | amzn    |            | 8.282.08.1-amzn
 Azul Zulu     |     | 16.0.0       | zulu    |            | 16.0.0-zulu
               |     | 16.0.0.fx    | zulu    |            | 16.0.0.fx-zulu
                                 [.....]
================================================================================
Use the Identifier for installation:

    $ sdk install java 11.0.3.hs-adpt
================================================================================

Do as the man says.

$ sdk install java 11.0.10.hs-adpt
[...]
$ java -version
openjdk version "11.0.10" 2021-01-19
OpenJDK Runtime Environment AdoptOpenJDK (build 11.0.10+9)
OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11.0.10+9, mixed mode)

Also get sbt.

$ sdk list scala
[...]
$ sdk install scala 2.13.5

$ sbt new sbt/scala-seed.g8
....
Minimum Scala build.

name [My Something Project]: hello

Template applied in ./hello
$ cd hello
$ sbt
> run

That should work.

Now open IntelliJ:

$ idea .

Open Preferences > Build, Execution, Deployment > Build Tools > sbt. And set JRE to Default which matches the active Java Virtual Machine.

Opening in VSCode if metals is installed automatically asks you’d like to import the project.

$ code .

Using sbt

$ sbt
sbt:hello> compile
sbt:hello> run

Prefix with a tilde to enable automatic recompilation upon file changes.

sbt:hello> ~compile

We can modify the build.sbt directly from the sbt shell.

sbt:hello> set ThisBuild / scalaVersion := "3.0.0-RC2"
sbt:hello> scalaVersion
[info] 3.0.0-RC2
sbt:hello> session save
sbt:hello2> exit
[info] shutting down sbt server
$ cat build.sbt 
ThisBuild / scalaVersion := "3.0.0-RC2"

To source the build.sbt file in an active sbt session, simply run the reload command.

sbt:hello> reload

To run tests.

sbt:hello> test

Or

sbt:hello> ~testQuick

Paste mode:

sbt:Hello> console
scala> :paste
{paste scala code}
{Ctrl-D}
// Exiting paste mode, now interpreting.

List projects in directory:

sbt:Hello> projects

Compile sub-project:

sbt:Hello> helloCore/compile

Package

sbt:Hello> dist

Dockerize

sbt:Hello> Docker/publishLocal

$ docker run hello:0.1.0-SNAPSHOT
Hello World!

Sources:

• https://www.scala-sbt.org/1.x/docs/Installing-sbt-on-Mac.html
• https://sdkman.io/
• https://www.scala-sbt.org/1.x/docs/sbt-by-example.html

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