The Adventurous Developers Guide to JVM Languages

This session was given at JavaOne 2015

There are more than 50 actively worked JVM languages in existence today. Some have been ported to the JVM, whereas others were written specifically for the JVM. This hands-on session takes an introductory (but non-Hello, World) look at several JVM languages, including Java 8, Scala, Groovy, Kotlin, Ceylon, and Xtend. It covers ZeroTurnaround’s initial experiences, including what rocked and sucked in learning each one. You don’t need any prior knowledge of these languages to attend the session. You will learn whether they are for you and will hear about some real-life experiences of trying these languages for the first time.

Transcript

1. THE ADVENTUROUS DEVELOPERS GUIDE TO JVM LANGUAGES SIMON MAPLE @SJMAPLE
2. SIMON MAPLE @SJMAPLE ABOUT ME
3. SIMON MAPLE @SJMAPLE VIRTUAL JUG FOUNDER LONDON JUG CO-LEADER JAVA CHAMPION JAVAONE ROCKSTAR REBELLABS AUTHOR ABOUT ME
4. ABOUT YOU 0 25 50 75 100 Heard of the Language Used the language Java Groovy Scala Kotlin Ceylon Xtend Fantom Clojure
5. JAVA “Most people talk about Java the language, and this may sound odd coming from me, but I could hardly care less.”
6. JAVA “Most people talk about Java the language, and this may sound odd coming from me, but I could hardly care less. At the core of the Java ecosystem is the JVM.” JAMES GOSLING, creator of the Java programming language (2011, TheServerSide)
7. JAVA JVM “Most people talk about Java the language, and this may sound odd coming from me, but I could hardly care less. At the core of the Java ecosystem is the JVM.” JAMES GOSLING, creator of the Java programming language (2011, TheServerSide)
8. LANGUAGES BUILT FOR THE JVM
9. LANGUAGES PORTED TO THE JVM
12. JAVA 8 1. Don’t break binary compatibility 2. Avoid introducing source incompatibilities 3. Manage behavioral compatibility changes
13. LET’S EXPERIMENT
15. COMPANION CLASS NO STATIC KEYWORD import HttpServer._
 // import statics from companion object
16. VARIABLES THERE IS NO FINAL KEYWORD val name: Type = initializer // immutable value 
 var name: Type = initializer // mutable variable
17. CASE CLASS case class Status(code: Int, text: String) !
 
 case method @ ("GET" | "HEAD") => ... case method => respondWithHtml( Status(501, "Not Implemented"), title = "501 Not Implemented", body = <H2>501 Not Implemented: { method } method</H2> ) ...
18. STRINGS val header = s""" |HTTP/1.1 ${status.code} ${status.text} |Server: Scala HTTP Server 1.0 |Date: ${new Date()} |Content-type: ${contentType} |Content-length: ${content.length} """.trim.stripMargin + LineSep + LineSep
19. NULL def toFile(file: File, isRetry: Boolean = false): Option[File] = if (file.isDirectory && !isRetry) toFile(new File(file, DefaultFile), true) else if (file.isFile) Some(file) else None
20. COMPLEXITY?
25. JAVA SUPERCHARGED!
26. NULL def streetName = user?.address?.street
27. ELVIS LIVES def displayName = user.name ?: "Anonymous"
28. CLOSURES square = { it * it } [ 1, 2, 3, 4 ].collect(square) // [1, 4, 9, 16]
29. COLLECTIONS def names = ["Ted", "Fred", "Jed", "Ned"] println names //[Ted, Fred, Jed, Ned] def shortNames = names.findAll { it.size() <= 3 } shortNames.each { println it } // Ted // Jed // Ned
30. GROOVY 2.0 - DYNATIC void someMethod() {} 
 void test() { sommeeMethod() } 

31. GROOVY 2.0 - DYNATIC import groovy.transform.TypeChecked void someMethod() {} @TypeChecked 
 void test() { sommeeMethod() } 

32. GROOVY 2.0 - DYNATIC import groovy.transform.TypeChecked void someMethod() {} @TypeChecked 
 void test() { //compilation error: //cannot find matching method sommeeMethod() sommeeMethod() } 

33. YAH, WE SAVE LIVES!
35. LET’S EXPERIMENT
37. LET’S EXPERIMENT
39. LET’S EXPERIMENT
40. SUMMARY Functions are first class citizens and should be treated as such!
41. SUMMARY EvErY-ONe’S 5YNT4X SuCkS...
42. SUMMARY …to someone else! EvErY-ONe’S 5YNT4X SuCkS...
43. SUMMARY The JVM is AWESOME
44. SUMMARY BE ADVENTUROUS! The JVM is AWESOME
45. YOU, ONE HOUR LATER 0 25 50 75 100 Heard of the Lang Java Groovy Scala Kotlin Ceylon Xtend Fantom Clojure
46. RESOURCES HTTPSERVER EXAMPLES OF EACH LANGUAGE ON GITHUB https://github.com/zeroturnaround/jvm-languages-report THE ADVENTUROUS DEVELOPERS GUIDE TO JVM LANGUAGES http://zeroturnaround.com/rebellabs/devs/the-adventurous-developers-guide-to-jvm-languages/
47. 47 FREE STUFF! 0t.ee/javaone-jr 0t.ee/javaone-xr