Richard Dallaway @d6y www.underscoreconsulting.com 

Agenda 1. Benefits of Scala 2. What it looks like 3. Why we trust it 4. How to start 

Benefits Productivity Maintainability Multi-core Developer Joy 

Without giving up... Performance Curly Braces Java Investment Tooling (but...) 

import org.joda.time.DateTime case class Subscription( owner: String, isTrial: Boolean, expiry: DateTime) val nextMonth = new DateTime().plusMonths(1) val sub = new Subscription( "Bob", isTrial = true, nextMonth) sub.owner // “Bob” sub == new Subscription( "Bob", true, nextMonth) // true 

val subs = List( Subscription("Anna", true, new DateTime()), ... ) val trials : List[Subscription] = subs.filter(s => s.isTrial) def expiring(sub: Subscription) : Boolean = daysBetween(now,sub.expiry).getDays < 2 val nagList = subs.filter(expiring) val expiringTrials = subs.filter(expiring).filter(_.isTrial) 

case class Sub(name: String, cc: Option[String]) val subs = List( Sub("Anna", None), Sub("Bob", Some("1234-5678-9123-4567")) ) def bill(cc: String) : Result = ... val results = subs.flatMap(s => s.cc).map(bill) val results = for { sub <- subs cc <- sub.cc } yield bill(cc) .par 

2003 2006 2009 2008 2011 2004 2005 2010 2007 2012 2013 2014 1.0 2.0 2.3 2.8 2.7 2.9 2.10 2.11 2.6 2.5 2.4 2.9.3 2.8.2 

The guy who built javac SpringSource VMware An advisor 

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Ideas for starting 1. Small project trial 2. Mixed Java/Scala projects 3. For tests 

@d6y @davegurnell @milessabin www.underscoreconsulting.com meetup.com/london-scala meetup.com/Functional-Brighton