Scala Basics
Run a small program with an entry point.
On this page
The concept
The main method is called when the program starts. val binds an immutable value, and println writes it.
Code example
Scala
object Main {
def main(args: Array[String]): Unit = {
val name = "Ada"
println(s"Hello, $name")
}
}Output
Hello, Ada
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1
object Main {2
def main(args: Array[String]): Unit = {3
val name = "Ada"4
println(s"Hello, $name")5
}6
}Follow the example
Start to inspect the source, values, and output. These prepared steps explain the published sample; grouped loop steps describe multiple iterations.
View the complete dry-run table
| Step / line | What happens | State after step | Output so far |
|---|---|---|---|
| Create immutable name when main runs. | name = "Ada" | — | |
| Interpolate name into the string and print. | name = "Ada" | Hello, Ada |
Behind the scenes
How Scala processes this code
Scala compiles for the JVM, which invokes the main entry point.