Scala Workflow

In this lesson, you will learn the complete Scala development workflow. This includes how Scala code is written, compiled, run, tested, and maintained in real projects.

Understanding the workflow helps you work efficiently and confidently on production-grade Scala applications.

What Is a Scala Workflow?

A Scala workflow is the step-by-step process followed while developing a Scala project.

It typically includes:

• Writing Scala source code
• Compiling the code
• Running the application
• Testing functionality
• Managing dependencies

Step 1: Writing Scala Code

Scala source files are written with the .scala extension and usually placed inside:

• src/main/scala for application code
• src/test/scala for test code

object HelloScala {
  def main(args: Array[String]): Unit = {
    println("Welcome to Scala Workflow")
  }
}

This file defines the program entry point.

Step 2: Compiling Scala Code

Compilation converts Scala source code into bytecode that runs on the JVM.

Using SBT, compilation is simple:

sbt compile

SBT only recompiles files that have changed, making the process fast.

Step 3: Running the Application

Once compiled, you can run the application using:

sbt run

SBT automatically detects the main method and executes it.

Step 4: Using the Interactive SBT Shell

Instead of running SBT commands repeatedly, you can start the interactive shell:

sbt

Inside the shell, you can run:

• compile
• run
• test

This speeds up development significantly.

Step 5: Managing Dependencies

Dependencies are managed in the build.sbt file.

Example:

libraryDependencies +=
  "com.typesafe" % "config" % "1.4.3"

SBT downloads and manages the library automatically.

Step 6: Testing Scala Code

Tests are written inside src/test/scala.

You can run all tests using:

sbt test

Testing ensures your application behaves as expected.

Step 7: Cleaning and Rebuilding

Sometimes you may want to clean all compiled files and rebuild the project.

sbt clean
sbt compile

This is useful when facing unexpected build issues.

Typical Scala Workflow Summary

• Write code in src/main/scala
• Add dependencies in build.sbt
• Compile using sbt compile
• Run using sbt run
• Test using sbt test

📝 Practice Exercises

Exercise 1

Create a Scala file with a main method.

Exercise 2

Compile and run the program using SBT.

Exercise 3

Add one external dependency to build.sbt.

✅ Practice Answers

Answer 1

object WorkflowDemo {
  def main(args: Array[String]): Unit = {
    println("Scala workflow running")
  }
}

Answer 2

sbt compile
sbt run

Answer 3

libraryDependencies +=
  "org.slf4j" % "slf4j-api" % "2.0.9"

What’s Next?

In the next lesson, you will start Functional Programming Basics, where Scala’s true power begins to shine.