Scala programming language is a high-level programming language that is statically typed and supports a fusion of object-oriented programming (OOP) and functional programming language (FP) paradigms.

Scala was designed by Martin Odersky a German Computer Scientist on 20th Jan 2004. Scala’s current latest release is scala 3.6.4 but the LTS is 3.3.5 . The word Scala comes from scalable. Scala is used for powering busy websites and analyze huge data sets.

Scala 3 features

Scala 3 has many terrific programming language features which include the following:

• It is a high level programming language
• It has concise readable syntax.
• It is statically typed.
• It is a functional programming language.
• It is an Object Oriented Programming language.
• It runs on JVM and in browsers.
• It interacts seamlessly with java code.
• It is used for server side applications, big data applications and browser with scala,js
• It has ability to create Algebraic Data Types (ADTs) concisely.
• It has a clear grammar making it easy to understand.

Why Scala 3

Scala 3 has many benefits and reasons why it is embraced by developers. We will list a few benefits.

• It embraces both Object Oriented Programming and Functional Programming Language.
• It is statically typed but feels dynamic.
• Its syntax is concise, readable and expressive.
• Has improved and simplified implicits.
• Integrates seamlessly with java making it easy to create projects with a mixture of the two languages.
• Scala can be used on the server, and also in the browser with scala.js
• Scala library has dozens of pre-built functional methods which saves time and reduce time for writing custom codes.
• Scala is a strong type system.

With the brief introduction of Scala 3, we now turn our focus on Scala3 installation in CentOS Stream 10.

There are 4 common ways of installing Scala 3 in CentOS 10.

1. Using Scala installer tool “Coursier”.
2. Using sbt which is the defacto build tool for Scala.
3. Using SDKMAN (Software Development Kit Manager).
4. Manual Installation.

In this article, we will briefly look at each installation method.

Method 1: Installation of Scala 3 in CentOS Stream 10 with Coursier

This is the recommended method of Scala installation. This method automatically installs all the Scala 3 dependencies.

Step 1 : Update CentOS Stream 10 system

Update the YUM packages:

sudo yum update -y

Step 2 : Install coursier native launcher.

After system update, install coursier launcher:

sudo yum install curl
curl -fL "https://github.com/coursier/launchers/raw/master/cs-x86_64-pc-linux.gz" | gzip -d > cs

Make cs executable with chmod command:

chmod +x cs 

Then add cs to your PATH:

./cs install cs
echo 'export PATH="$PATH:~/.local/share/coursier/bin"' | tee -a ~/.bashrc
source ~/.bashrc

Complete cs installation & update cs.

rm cs
cs update cs

Step 3 : Install JVM and standard Scala CLI tools

To install Java 11, download the binary release:

wget https://download.java.net/java/ga/jdk11/openjdk-11_linux-x64_bin.tar.gz

Then extract it:

sudo mkdir -p /opt/java
sudo tar -xvzf openjdk-11_linux-x64_bin.tar.gz -C /opt/java

Set JAVA_HOME variable:

cat << 'EOF' >> ~/.bashrc
export JAVA_HOME=/opt/java/jdk-11
export PATH=$JAVA_HOME/bin:$PATH
EOF

To install JVM and standard Scala CLI tools, run the setup command:

cs setup --yes

The command output:

The cs setup command automatically installs JVM and other useful command-line tools.

Step 4 : Install Scala3 and scala3-compiler

To install Scala3 compiler and runner as command-line tools, run the commands:

cs install scala3-compiler
cs install scala3
exit

Confirm version installed:

$ scala -version
Scala code runner version: 1.5.4
Scala version (default): 3.6.4

You have successfully installed Scala using coursier.

Method 2: Installation of Scala 3 on CentOS Stream 10 using sbt

sbt is a build tool for Scala, Java, and many more. It requires Java 1.8 or later for a successful installation.

Step 1 : Install java 1.8 or later

To install Java 11 run the command, download it:

wget https://download.java.net/java/ga/jdk11/openjdk-11_linux-x64_bin.tar.gz

Then extract it:

sudo mkdir -p /opt/java
sudo tar -xvzf openjdk-11_linux-x64_bin.tar.gz -C /opt/java

Set the “JAVA_HOME” environment variable:

cat << 'EOF' >> ~/.bashrc
export JAVA_HOME=/opt/java/jdk-11
export PATH=$JAVA_HOME/bin:$PATH
EOF

Verify java version installed:

$ java -version
openjdk 11 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)

Step 2 : Install sbt

To install sbt execute the following commands:

Remove the old Bintray repo file:

sudo rm -f /etc/yum.repos.d/bintray-rpm.repo

Then add the sbt-rpm repository:

curl -L https://www.scala-sbt.org/sbt-rpm.repo > sbt-rpm.repo

Move the sbt-rpm repo to yum.repos.d:

sudo mv sbt-rpm.repo /etc/yum.repos.d/

Finally, install sbt:

sudo yum update
sudo yum install sbt

Verify sbt installation:

$ sbt --version
downloading sbt launcher 1.10.11
copying runtime jar...
sbt runner version: 1.10.11

[info] sbt runner (sbt-the-shell-script) is a runner to run any declared version of sbt.
[info] Actual version of the sbt is declared using project/build.properties for each build.

Then update & refresh the YUM packages.

sudo yum update -y

Step 3 : Helloworld example using sbt

Create a simple HelloWorld application with the command below:

$ sbt new sbt/scala-seed.g8

Sample Output:

Run the HelloWorld application:

Change to ~/./helloworld and issue sbt command:

$ cd ~/./helloworld
$ sbt

Sample Output:

Then issue the command run:

sbt:HelloWorld> run 

Sample Output:

To exit the sbt shell, type exit or use Ctrl+D.

Method 3: Installing Scala3 on CentOS Stream 10 from SDKMAN

Install Java 11

To install Java 11 run the command, download it:

wget https://download.java.net/java/ga/jdk11/openjdk-11_linux-x64_bin.tar.gz

Then extract it:

sudo mkdir -p /opt/java
sudo tar -xvzf openjdk-11_linux-x64_bin.tar.gz -C /opt/java

Set the “JAVA_HOME” environment variable:

cat << 'EOF' >> ~/.bashrc
export JAVA_HOME=/opt/java/jdk-11
export PATH=$JAVA_HOME/bin:$PATH
EOF

Verify java version installed:

$ java -version
openjdk 11 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)

Install Sdkman

To install sdkman, paste the following command on the terminal:

curl -s "https://get.sdkman.io" | bash

Sample output:

Source the file:

source "/home/cloudspinx/.sdkman/bin/sdkman-init.sh"

To verify your installation:

sdk version

The output :

Install Scala3 using SDK

To install Scala3 using SDK execute the command:

sdk install scala

Output :

From the output, Scala version 3.1.0 has been installed.

Verify SDK installation:

scala -version

Sample output:

Scala code runner version: 1.5.4
Scala version (default): 3.6.4

Method 4: Manual installation of Scala 3 on CentOS Stream 10

Download and install the latest Scala 3 RPM file from the official Github Release page.

Scala binaries for s are available as of this article.

sudo yum update -y
sudo yum install curl -y
VER=$(curl -s https://api.github.com/repos/scala/scala3/releases/latest|grep tag_name|cut -d '"' -f 4|sed 's/v//')
sudo wget https://github.com/scala/scala3/releases/download/${VER}/scala3-${VER}.tar.gz

After download, extract the file.

tar -xf scala3-${VERSION}.tar.gz

Then move the directory created to /usr/local/share/scala:

sudo mv scala3-${VERSION}/ /usr/local/share/scala

Next Install Java. To install Java 11 run the command, download it:

wget https://download.java.net/java/ga/jdk11/openjdk-11_linux-x64_bin.tar.gz

Then extract it:

sudo mkdir -p /opt/java
sudo tar -xvzf openjdk-11_linux-x64_bin.tar.gz -C /opt/java

Set the “JAVA_HOME” environment variable:

cat << 'EOF' >> ~/.bashrc
export JAVA_HOME=/opt/java/jdk-11
export PATH=$JAVA_HOME/bin:$PATH
EOF

Verify java version installed:

$ java -version
openjdk 11 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)

Verify Scala version installed:

$ scala -version
Scala code runner version: 1.5.4
Scala version (default): 3.6.4

That marks the end of manual Scala 3 installation in CentOS Stream 10.

Creating a Scala 3 project in CentOS Stream 10

With Scala 3 installation now complete, let’s run a simple project for demonstration purposes.

In this example, I will add two integers and run the HelloWorld application using Scala.

Step 1 : Get into Scala Shell.

To get into scala shell, run the scala command:

scala

Step 2 : Calculate the result of a formula.

Add two integers to get the sum.

scala> 3+5

The output:

scala> 3+5
val res1: Int = 8

You can as well execute a function. Let’s demonstrate a HelloWorld application.

scala> println("HelloWorld")

This command prints HelloWorld

scala> println ("Hello World!!")
Hello World!!

To quit the scala shell:

:q

You can also use scalac compiler to compile a .scala source code.

1. Create a .scala source code.

Use a text editor to create a .scala source code.

vim hello.scala

Paste the code below:

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

Save and exit your terminal.

:wq

2. Compile your .scala source code.

To compile the source code, use scalac

scalac run hello.scala

The output :

Congratulations you have compiled your first hello world application with scala.

To uninstall the Scala package:

sudo dnf remove scala

Conclusion:

That marks the end of the article on How To Install Scala 3 on CentOS Stream 10. Many developers would appreciate Scala because of its unique features and its seamless interaction with java code. I hope the article was relevant to you and thank you for following.

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