{{libheader|Console}}
===Ad hoc REPL solution===
Ad hoc solution as [http://en.wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop REPL] script. Type this in a REPL session:
println("Hello world!")
===Via Java runtime===
This is a call to the Java run-time library. '''Not recommended'''.
System.out.println("Hello world!")

===Via Scala Console API===
This is a call to the Scala run-time library. '''Recommended'''.
println("Hello world!")

===Short term deviation to out===
Console.withErr(Console.out) { Console.err.println("This goes to default _out_") }
===Long term deviation to out===
  Console.err.println ("Err not deviated")
  Console.setErr(Console.out)
  Console.err.println ("Err deviated")
  Console.setErr(Console.err) // Reset to normal