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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, Xtend, and Clojure. 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.
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THE ADVENTUROUS DEVELOPERS GUIDE TO JVM LANGUAGES
SIMON MAPLE @SJMAPLE
Monday, 30 September 13
Monday, 30 September 13
YOUR SPEAKER
SIMON MAPLE @SJMAPLE
Monday, 30 September 13
MY AUDIENCE
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Heard of the Language Used the languageJava Scala Groovy Clojure Ceylon Kotlin Xtend
Monday, 30 September 13
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)
Monday, 30 September 13
JAVA THE 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)
Monday, 30 September 13
LANGUAGES BUILT FOR THE JVM
Monday, 30 September 13
LANGUAGES PORTED TO THE JVM
Monday, 30 September 13
R.I.P ?
Monday, 30 September 13
Monday, 30 September 13
Monday, 30 September 13
JAVA 8
1. DON’T BREAK BINARY COMPATIBILITY
2. AVOID INTRODUCING SOURCE INCOMPATIBILITIES
3. MANAGE BEHAVIORAL COMPATIBILITY CHANGES
Monday, 30 September 13
LET’S EXPERIMENT
Monday, 30 September 13
Monday, 30 September 13
COMPANION CLASS
THERE IS NO STATIC
import HttpServer._ // import statics from companion object
Monday, 30 September 13
VARIABLES
THERE IS NO FINAL
val name: Type = initializer // immutable value
var name: Type = initializer // mutable variable
Monday, 30 September 13
CASE CLASScase 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> ...
Monday, 30 September 13
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
Monday, 30 September 13
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
Monday, 30 September 13
COMPLEXITY
Monday, 30 September 13
Monday, 30 September 13
Monday, 30 September 13
Monday, 30 September 13
Monday, 30 September 13
JAVA SUPERCHARGED!
Monday, 30 September 13
NULL
def streetName = user?.address?.street
Monday, 30 September 13
ELVIS LIVES
def displayName = user.name ?: "Anonymous"
Monday, 30 September 13
CLOSURES
square = { it * it }
[ 1, 2, 3, 4 ].collect(square) // [1, 4, 9, 16]
Monday, 30 September 13
COLLECTIONS
def names = ["Ted", "Fred", "Jed", "Ned"]
5p[5 println names //[Ted, Fred, Jed, Ned]
def shortNames = names.findAll { it.size() <= 3 }
shortNames.each { println it } // Ted // Jed // Ned
Monday, 30 September 13
GROOVY 2.0 - DYNATIC
void someMethod() {}
void test() {
sommeeMethod()}
Monday, 30 September 13
GROOVY 2.0 - DYNATIC
void someMethod() {}
void test() {
sommeeMethod()}
import groovy.transform.TypeChecked
@TypeChecked
Monday, 30 September 13
GROOVY 2.0 - DYNATIC
void someMethod() {}
void test() {
sommeeMethod()}
// compilation error: // cannot find matching method sommeeMethod()
import groovy.transform.TypeChecked
@TypeChecked
Monday, 30 September 13
Monday, 30 September 13
Founder/CEO Jevgeni “Hosselhuff” Kabanov gets ready to save more Java developers from redeploy madness with JRebel
YEH, WE SAVE LIVES
Monday, 30 September 13
Monday, 30 September 13
REPL
<Python user> Can you believe these JVM geeks think this is impressive?<Perl user> Tell me about it! Welcome to the 90s<Python user> Yeh, “Hey the 20th century called to say they wanted their code back”!<Groovy user> Hey, we do this too!
Monday, 30 September 13
FUNCTIONAL PRINCIPLES1. LITTLE OR NO SIDE EFFECTS
2. FUNCTIONS SHOULD ALWAYS RETURN THE SAME RESULT IF CALLED WITH THE SAME PARAMETERS
3. NO GLOBAL VARIABLES
4. FUNCTIONS AS FIRST ORDER CITIZENS
5. LAZY EVALUATION OF EXPRESSIONS
Monday, 30 September 13
WHOA!
(defn send-html-response "Html response" [client-socket status title body] (let [html (str "<HTML><HEAD><TITLE>" title "</TITLE></HEAD><BODY>" body "</BODY></HTML>")] send-http-response client-socket status "text/html" (.getBytes html "UTF-8")) ))
Monday, 30 September 13
LET’S GET FUNCTIONAL
(defn process-request "Parse the HTTP request and decide what to do" [client-socket] (let [reader (get-reader client-socket) first-line (.readLine reader) tokens (clojure.string/split first-line #"\s+")] (let [http-method (clojure.string/upper-case (get tokens 0 "unknown"))] (if (or (= http-method "GET") (= http-method "HEAD")) (let [file-requested-name (get tokens 1 "not-existing") [...]
Monday, 30 September 13
INTEROP
(ns clojure-http-server.core (:require [clojure.string]) (:import (java.net ServerSocket SocketException) (java.util Date) (java.io PrintWriter BufferedReader InputStreamReader BufferedOutputStream)))
Monday, 30 September 13
Monday, 30 September 13
LET’S EXPERIMENT
Monday, 30 September 13
Monday, 30 September 13
LET’S EXPERIMENT
Monday, 30 September 13
Monday, 30 September 13
LET’S EXPERIMENT
Monday, 30 September 13
SUMMARY
FUNCTIONS ARE FIRST CLASS CITIZENS
AND SHOULD BE TREATED AS SUCH!
Monday, 30 September 13
SUMMARY
STATICALLY TYPED LANGUAGES ROCK
Monday, 30 September 13
SUMMARY
EVERYONE’S SYNTAX SUCKS...
Monday, 30 September 13
SUMMARY
EVERYONE’S SYNTAX SUCKS...
TO SOMEONE ELSE.
Monday, 30 September 13
SUMMARY
THE JVM IS AWESOME
Monday, 30 September 13
BE ADVENTUROUS!
Monday, 30 September 13
YOU, ONE HOUR LATER
0
25
50
75
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Heard of the Lang
Java Scala Groovy Clojure Ceylon Kotlin Xtend
Monday, 30 September 13
REBEL LABS == AWESOME
99.9% NON-PRODUCT RELATED
TECH REPORTS WRITTEN BY OUR DEVELOPERS
Monday, 30 September 13
REBEL LABS == AWESOME
JAVA 8, CONTINUOUS DELIVERY,
APP SERVER DEBATE, JVM WEB FRAMEWORKS,
PRODUCTIVITY REPORTS...
Monday, 30 September 13
REBEL LABS == AWESOME
AND...
THE ADVENTUROUS DEVELOPERS GUIDE TO JVM LANGUAGES
Monday, 30 September 13
RESOURCES
HTTPSERVER EXAMPLES OF EACH LANGUAGE ON GITHUBhttps://github.com/zeroturnaround/jvm-languages-report
THE ADVENTUROUS DEVELOPERS GUIDE TO JVM LANGUAGEShttp://zeroturnaround.com/rebellabs/devs/the-adventurous-developers-guide-to-jvm-languages/
Monday, 30 September 13
RESOURCES
SIMON MAPLE@SJMAPLE
Monday, 30 September 13
Monday, 30 September 13
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