Lucky Seven Neuerungen in Java 7 Wolfgang Weigend Oracle - - PowerPoint PPT Presentation

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Lucky Seven Neuerungen in Java 7 Wolfgang Weigend Oracle Deutschland B.V. & Co. KG P NeuerungeninJava7 <InsertPictureHere> Diewichtigsten nderungen,Erweiterungen

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SLIDE 1

Lucky Seven

Neuerungen in Java 7

Wolfgang Weigend

Oracle Deutschland B.V. & Co. KG

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SLIDE 2

<InsertPictureHere>

NeuerungeninJava7 Diewichtigsten Änderungen,Erweiterungen

P

  • WolfgangWeigend

SystemberaterJavaTechnologieundArchitektur

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SLIDE 3

PrioritiesfortheJavaPlatforms

GrowDeveloperBase GrowAdoption IncreaseCompetitiveness IncreaseCompetitiveness Adapttochange

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SLIDE 4

JavaCommunities

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SLIDE 5

HowJavaEvolvesandAdapts

CommunityDevelopmentof JavaTechnologySpecifications

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SLIDE 6

JCPReforms

  • Developers voiceintheExecutiveCommittee
  • SOUJava
  • GoldmanSachs
  • LondonJavaCommunity
  • AlexTerrazas
  • JCPstartingaprogramofreform
  • JCPstartingaprogramofreform
  • JSR348:TowardsanewversionoftheJCP
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SLIDE 7

EvolvingtheLanguage

From“EvolvingtheJavaLanguage” - JavaOne2005

  • Javalanguageprinciples

– Readingismoreimportantthanwriting – Codeshouldbeajoytoread – Thelanguageshouldnothidewhatishappening – Codeshoulddowhatitseemstodo – Simplicitymatters – Every“good” featureaddsmore“bad” weight 6

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– Every“good” featureaddsmore“bad” weight – Sometimesitisbesttoleavethingsout

  • Onelanguage:withthesamemeaningeverywhere
  • Nodialects
  • WewillevolvetheJavalanguage
  • Butcautiously,withalongtermview
  • “firstdonoharm”
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SLIDE 8

Soyouwanttochangethelanguage?

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SLIDE 9

JavaSE7ReleaseContents

  • JavaLanguage
  • ProjectCoin(JSR-334)
  • ClassLibraries
  • NIO2(JSR-203)
  • Fork-Joinframework,ParallelArray (JSR-166y)

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  • Fork-Joinframework,ParallelArray (JSR-166y)
  • JavaVirtualMachine
  • TheDaVinci Machineproject(JSR-292)
  • InvokeDynamic bytecode
  • MiscellaneousThings
  • JSR-336:JavaSE7ReleaseContents
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SLIDE 10

<InsertPictureHere>

Section Divider

Small Small Language Language

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Language Language Changes Changes

ProjectCoin ProjectCoin

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SLIDE 11

ProjectCoinConstraints

  • Small languagechanges
  • Smallinspecification,implementation,testing
  • Nonewkeywords!
  • Waryoftypesystemchanges

Coordinatewithlargerlanguagechanges

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  • Coordinatewithlargerlanguagechanges

– ProjectLambda – Modularity

  • Onelanguage,onejavac
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SLIDE 12

BetterIntegerLiteral

  • Binaryliterals

intmask=0b101010101010;

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  • Withunderscoresforclarity

intmask=0b1010_1010_1010; longbig=9_223_783_036_967_937L;

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SLIDE 13

StringSwitchStatement

  • Todaycaselabelincludesintegerconstantsand

enumconstants

  • Stringsareconstantstoo(immutable)

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SLIDE 14

DistinguishStringsToday

intmonthNameToDays(Strings,intyear){ if("April".equals(s)||"June".equals(s)|| "September".equals(s)||"November".equals(s)) return30; if("January".equals(s)||"March".equals(s)||

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if("January".equals(s)||"March".equals(s)|| "May".equals(s)||"July".equals(s)|| "August".equals(s)||"December".equals(s)) return31; if("February".equals(s)) ...

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SLIDE 15

StringsinSwitchStatements

intmonthNameToDays(Strings,intyear){ switch(s){ case"April":case"June": case"September":case"November": return30; case"January":case"March":

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case"May":case"July": case"August":case"December": return31; case"February”: ... default: ...

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SLIDE 16

SimplifyingGenerics

  • Pre-generics

ListstrList=newArrayList();

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SLIDE 17

SimplifyingGenerics

  • Pre-generics

ListstrList=newArrayList();

  • WithGenerics

List<String> strList=newArrayList<String>();

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List<String> strList=newArrayList<String>();

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SLIDE 18

SimplifyingGenerics

  • Pre-generics

ListstrList=newArrayList();

  • WithGenerics

List<String> strList=newArrayList<String>();

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List<String> strList=newArrayList<String>(); List<Map<String,List<String>> strList= newArrayList<Map<String,List<String>>();

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SLIDE 19

DiamondOperator

  • Pre-generics

ListstrList=newArrayList();

  • WithGenerics

List<String> strList=newArrayList<String>();

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  • Withdiamond(<>)compilerinferstype

List<Map<String,List<String>> strList= newArrayList<Map<String,List<String>>(); List<String> strList=newArrayList<>(); List<Map<String,List<String>> strList= newArrayList<>();

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SLIDE 20

CopyingaFile

InputStreamin=newFileInputStream(src); OutputStreamout=newFileOutputStream(dest); byte[]buf=newbyte[8192]; intn;

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while(n=in.read(buf))>=0)

  • ut.write(buf,0,n);
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SLIDE 21

CopyingaFile(Better,butwrong)

InputStreamin=newFileInputStream(src); OutputStreamout=newFileOutputStream(dest); try{ byte[]buf=newbyte[8192];

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intn; while(n=in.read(buf))>=0)

  • ut.write(buf,0,n);

}finally{ in.close();

  • ut.close();

}

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SLIDE 22

CopyingaFile(Correct,butcomplex)

InputStreamin=newFileInputStream(src); try{ OutputStreamout=newFileOutputStream(dest); try{ byte[]buf=newbyte[8192]; intn; while(n=in.read(buf))>=0)

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while(n=in.read(buf))>=0)

  • ut.write(buf,0,n);

}finally{

  • ut.close();

} }finally{ in.close(); }

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SLIDE 23

CopyingaFile(Correct,butcomplex)

InputStreamin=newFileInputStream(src); try{ OutputStreamout=newFileOutputStream(dest); try{ byte[]buf=newbyte[8192]; intn; while(n=in.read(buf))>=0)

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while(n=in.read(buf))>=0)

  • ut.write(buf,0,n);

}finally{

  • ut.close();

} }finally{ in.close(); }

Exceptionthrownfrom potentiallythreeplaces. Detailsoffirsttwocouldbelost

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SLIDE 24

AutomaticResourceManagement

try(InputStreamin=newFileInputStream(src), OutputStreamout=newFileOutputStream(dest)) { byte[]buf=newbyte[8192]; intn; while(n=in.read(buf))>=0)

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while(n=in.read(buf))>=0)

  • ut.write(buf,0,n);

}

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TheDetails

  • Compilerde-sugarstry-with-resourcesintonestedtry-

finallyblockswithvariablestotrackexceptionstate

  • Suppressedexceptionsarerecordedforposterity

usinganewfacilityofThrowable

  • APIsupportinJDK7

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  • APIsupportinJDK7
  • Newsuperinterfacejava.lang.AutoCloseable
  • AllAutoCloseable andbyextensionjava.io.Closeabletypes

useablewithtry-with-resources

  • Anythingwithavoidclose() methodisacandidate
  • JDBC4.1retro-fittedasAutoCloseable too
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SLIDE 26

MoreInformativeBacktraces

java.io.IOException atSuppress.write(Suppress.java:19) atSuppress.main(Suppress.java:8) Suppressed: java.io.IOException at Suppress.close(Suppress.java:24)

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at Suppress.close(Suppress.java:24) at Suppress.main(Suppress.java:9) Suppressed: java.io.IOException at Suppress.close(Suppress.java:24) at Suppress.main(Suppress.java:9)

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SLIDE 27

VarargsWarnings

classTest{ publicstaticvoidmain(String...args){ List<List<String>>monthsInTwoLanguages= Arrays.asList(Arrays.asList("January", "February"), Arrays.asList("Enero", "Febrero")); 26

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} } Test.java:7: warning: [unchecked] unchecked generic array creation for varargsparameter of type List<String>[] Arrays.asList(Arrays.asList("January", ^ 1 warning

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HeapPollution– JLSv34.12.2.1

  • Avariableofaparameterizedtypereferstoanobject

thatisnotofthatparameterizedtype

  • Forexample,thevariableoftypeList<String>[]

mightpointtoanarrayofListswheretheListsdid notcontainstrings

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notcontainstrings

  • ReportspossiblelocationsofClassCastExceptions

atruntime

  • Aconsequenceoferasure
  • Possiblyproperlyaddressedbyreificationinthefuture
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SLIDE 29

VarargsWarningsRevised

  • Newmandatorycompilerwarningatsuspectvarargs

methoddeclarations

  • Byapplyinganannotationatthedeclaration,

warningsatthedeclarationandcallsites canbe suppressed

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suppressed

  • @SuppressWarnings(value=“unchecked”)
  • @SafeVarargs
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SLIDE 30

LotsofExceptions

try{ ... }catch(ClassNotFoundExceptioncnfe){ doSomethingClever(cnfe); throwcnfe; }catch(InstantiationExceptionie){ log(ie); throwie;

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throwie; }catch(NoSuchMethodExceptionnsme){ log(nsme); thrownsme; }catch(InvocationTargetExceptionite){ log(ite); throwite; }

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SLIDE 31

Multi-Catch

try{ ... }catch(ClassCastExceptione){ doSomethingClever(e); throwe; }catch(InstantiationException|

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NoSuchMethodException| InvocationTargetExceptione){ log(e); throwe; }

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SLIDE 32

IDESupport

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SLIDE 33

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SLIDE 34

NewI/O2(NIO2)Libraries

  • OriginalJavaI/OAPIspresentedchallengesfordevelopers
  • Needsomethingbetterthanjava.io.File
  • Doesn'tworkconsistentlyacrossplatforms
  • Nousefulexceptionswhenafileoperationfails
  • Missingbasicoperations(filecopy,move,...)

JSR203

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  • Missingbasicoperations(filecopy,move,...)
  • Limitedsupportforsymboliclinks
  • Limitedsupportforfileattributes,performanceissues
  • Nowaytoplug-inotherfilesystemimplementations
  • JavaNIO2solvestheseproblems
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SLIDE 35

JavaNIO2Features

  • PathisareplacementforFile

− Biggestimpactondevelopers

  • Betterdirectorysupport
  • Files

− Staticmethodstooperateonfilesanddirectories Supportforsymboliclinks

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− Supportforsymboliclinks

  • FileStore

− Representsunderlyingfilestorage(partition,concretefilesystem)

  • FileSystem

− SPIinterfacetoafilesystem(FAT,ZFS,Ziparchive,network,etc)

  • Accesstofilemetadata
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SLIDE 36

Path Class

  • Equivalentofjava.io.File inthenewAPI

– Immutable

  • HavemethodstoaccessandmanipulatePath
  • Supportsoldlibraries

− CreateFilefromPathusingtoFile //Makeareferencetothepath

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//Makeareferencetothepath Pathhome=Paths.get(“/home/fred”); //Resolvetmpfrom/home/fred->/home/fred/tmp PathtmpPath=home.resolve(“tmp”); //Createarelativepathfromtmp->.. PathrelativePath=tmpPath.relativize(home) Filefile=relativePath.toFile();

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SLIDE 37

FileOperation– Copy,Move

  • Filecopyisreallyeasy

– Withfinegraincontrol Pathsrc=Paths.get(“/home/fred/readme.txt”); Pathdst=Paths.get(“/home/fred/copy_readme.txt”); Files.copy(src,dst, StandardCopyOption.COPY_ATTRIBUTES,

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  • Filemoveissupported

– Optionalatomicmovesupported StandardCopyOption.COPY_ATTRIBUTES, StandardCopyOption.REPLACE_EXISTING); Pathsrc=Paths.get(“/home/fred/readme.txt”); Pathdst=Paths.get(“/home/fred/readme.1st”); Files.move(src,dst,StandardCopyOption.ATOMIC_MOVE);

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Directories

  • DirectoryStreamiterateoverentries

– Scalestolargedirectories – Useslessresources – Smoothoutresponsetimeforremotefilesystems – ImplementsIterable andCloseable forproductivity

  • Filteringsupport

Build-insupportforglob,regexandcustomfilters

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– Build-insupportforglob,regexandcustomfilters PathsrcPath=Paths.get(“/home/fred/src”); try(DirectoryStream<Path>dir= srcPath.newDirectoryStream(“*.java”)){ for(Pathfile:dir) System.out.println(file.getName()); }

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SLIDE 39

ConcurrencyAPIs

  • JSR166y

− UpdatetoJSR166xwhichwasanupdatetoJSR166

  • Addsalightweighttaskframework

− AlsoreferredtoasFork/Join

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  • Phaser

− BarriersimilartoCyclicBarrier andCountDownLatch

  • TransferQueue interface

− ExtensiontoBlockingQueue − ImplementedbyLinkedTransferQueue

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SLIDE 40

ForkJoinFramework

  • Goalistotakeadvantageofmultipleprocessor
  • Designedfortaskthatcanbebrokendowninto

smallerpieces

– Eg.Fibonaccinumberfib(10)=fib(9)+fib(8)

  • Typicalalgorithmthatusesforkjoin

join fork 39

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ifIcanmanagethetask performthetask else forktaskintox numberofsmaller/similartask jointheresults

join fork

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KeyClasses

  • ForkJoinPool

– ExecutorserviceforrunningForkJoinTask

  • ForkJoinTask

– Thebaseclassforforkjointask

  • RecursiveAction

– AsubclassofForkJoinTask Arecursiveresultlesstask

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– Arecursiveresultlesstask – Implementscompute() abstractmethodtoperformcalculation

  • RecursiveTask

– SimilartoRecursiveAction butreturnsaresult

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SLIDE 42

ForkJoinExample– Fibonacci

publicclassFibonacciextendsRecursiveTask<Integer>{ privatefinalintnumber; publicFibonacci(intn){number=n;} @OverrideprotectedIntegercompute(){ switch(number){ case0:return(0); case1:return(1); default: 41

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default: Fibonaccif1=newFibonacci(number– 1); Fibonaccif2=newFibonacci(number– 2); f1.fork();f2.fork(); return(f1.join()+f2.join()); } } }

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SLIDE 43

ForkJoinExample– Fibonacci

ForkJoinPoolpool=newForkJoinPool(); Fibonaccir=newFibonacci(10); pool.submit(r); while(!r.isDone()){ //Dosomework

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//Dosomework ... } System.out.println("Resultoffib(10)=" +r.get());

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SLIDE 44

ForkJoinPerformanceDiscussion

  • Choosingthesequentialthreshold

− Smallertasksincreaseparallelism − Largertasksreducecoordinationoverhead − Ultimatelyyoumustprofileyourcode

  • Minimizesoverheadforcompute-intensivetasks

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  • Minimizesoverheadforcompute-intensivetasks

− NotrecommendedfortasksthatmixCPUandI/Oactivity

  • Aportablewaytoexpressmanyparallelalgorithms

− Reasonablyefficientforawiderangeofcorecounts − Library-managedparallelism

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SLIDE 45

ClientLibraries

  • NimbusLookandFeel
  • PlatformAPIsforshapedandtranslucentwindows
  • JLayer(formerlyfromSwinglabs)
  • Optimized2Drendering

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  • Optimized2Drendering
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SLIDE 46

NimbusLookandFeel

  • BetterthanMetalforcrossplatformlook-and-feel
  • IntroducedinJavaSE6u10,nowpartofSwing
  • NotthedefaultL&F

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SLIDE 47

JLayercomponent

EasyenrichmentforSwingcomponents

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SLIDE 48

JLayercomponent

Theuniversaldecorator

  • TransparentdecoratorforaSwingcomponent
  • Controlsthepaintingofitssubcomponents
  • Catchesallinputandfocuseventsforthewholehierarchy

//wrapyourcomponentwithJLayer JLayer<JPanel>layer =newJLayer<JPanel>(panel);

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JLayer<JPanel>layer =newJLayer<JPanel>(panel); //customuiprovidesallextrafunctionality layer.setUI(myLayerUI); //addthelayerasusualcomponent frame.add(layer);

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SLIDE 49

TheDaVinciMachineProject(JSR-292)

(Amulti-languagerenaissancefortheJVM)

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Better

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SLIDE 50

LanguagesLikeVirtualMachines

  • Programminglanguagesneedruntimesupport

− Memorymanagement/Garbagecollection − Concurrencycontrol − Security Reflection

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− Reflection − Debuggingintegration − Standardlibraries

  • Compilerwritershavetobuildthesefromscratch
  • TargetingaVMallowsreuseofinfrastructure
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SLIDE 51

JVMSpecification

“TheJava virtualmachineknows nothingabouttheJava programminglanguage,onlyofa

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particularbinaryformat,theclass fileformat.”

1.2TheJavaVirtualMachineSpec.

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SLIDE 52

LanguagesRunningontheJVM

Groovy JRuby … …

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… Scala Clojure

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SLIDE 53

InvokeDynamicBytecode

  • JVMcurrentlyhasfourwaystoinvokemethod

− Invokevirtual,invokeinterface,invokestatic,invokespecial

  • Allrequirefullmethodsignaturedata
  • InvokeDynamicwillusemethodhandle

− Effectivelyanindirectpointertothemethod

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  • Whendynamicmethodisfirstcalledbootstrapcode

determinesmethodandcreateshandle

  • Subsequentcallssimplyreferencedefinedhandle
  • Typechangesforceare-computeofthemethod

locationandanupdatetothehandle

− Methodcallchangesareinvisibletocallingcode

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SLIDE 54

CallSite andMethodHandle

  • invokedynamic linkedtoaCallSite

– CallSite canbelinkedorunlinked – CallSite holderofMethodHandle

  • MethodHandle isadirectlyexecutablereferenceto

anunderlyingmethod,constructor,field

– Cantransformargumentsandreturntype Transformation– conversion,insertion,deletion,substitution

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– Transformation– conversion,insertion,deletion,substitution

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SLIDE 55

invokedynamic Step1-to-4

this[method_name](x,y)

invokedynamic [#bootstrapMethod] .this_method_name

classLanguageRuntime{ bootstrapMethod(info){ ... 1.Invokebootstrap 2.Produces CallSite 3.Completelinkage

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... returnnewCallSite(); } classAClass{ aMethod(x,y){ ... } CallSite Method Handle 3.Completelinkage 4.Invokesmethod implementation

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SLIDE 56

MiscellaneousThings

  • Security
  • Ellipticcurvecryptography
  • TLS1.2
  • JAXP1.4.4
  • JAX-WS2.2

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  • JAX-WS2.2
  • JAXB2.2
  • ClassLoaderarchitecturechanges
  • close() forURLClassLoader
  • JavadocsupportforCSS
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SLIDE 57

JDK7PlatformSupport

  • Windowsx86

− Server2008,Server2008R2,7&8(whenitGAs) − WindowsVista,XP

  • Linuxx86

− OracleLinux5.5+,6.x − RedHatEnterpriseLinux5.5+,6.x − SuSE LinuxEnterpriseServer10.x,11.x Ubuntu Linux10.04LTS,11.04

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− Ubuntu Linux10.04LTS,11.04

  • Solarisx86/SPARC

− Solaris10.9+,11.x

  • AppleOSXx86

− Willbesupportedpost-GA,detailedplanTBD Note:JDK7shouldrunonprettymuchanyWindows/Linux/Solaris. TheseconfigurationsaretheonesprimarilytestedbyOracle,andfor whichweprovidecommercialsupport.

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SLIDE 58

JVMConvergence– Forwardlooking

Project“HotRockit”

  • Hotspot 21
  • JavaSE7Support
  • Rebranding
  • Improved JMX

Agent

  • Commandline

servicabilitytool

JDK7GA– 07/11

  • Hotspot 22
  • Performance
  • Enablelargeheaps

withreasonable latencies

JDK7u2

  • Hotspot 23
  • More performance
  • Improvedcommand

lineservicability (jcmd)

  • Enablelargeheaps

withconsistent reasonablelatencies

JDK7uX

  • Hotspot24
  • JavaSE8Support
  • Allperformance

featuresfrom JRockitported

  • Allservicability

featuresfrom JRockitported

JDK8GA

servicabilitytool (jrcmd)

  • -- Premium---
  • Improved JRockit

MissionControl Consolesupport reasonablelatencies

  • NoPermGen
  • -- Premium---
  • CompleteJRockit

FlightRecorder Support JRockitported

  • Compilercontrols
  • Verboselogging
  • -- Premium---
  • JRockitMission

ControlMemleak ToolSupport

  • SoftRealTimeGC
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SLIDE 59

ProjectLambda(JSR335)

Closuresandlambdaexpressions

ProjectJigsaw(JSR-294)

ModularizingtheJavaPlatform

JavaSE8

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MoreProjectCoin

SmallLanguageChanges Closuresandlambdaexpressions Bettersupportformulti-coreprocessors

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SLIDE 60

Zusammenfassung

  • JavaSE7
  • Incrementalchanges
  • Evolutionary,notrevolutionary
  • Goodsolidsetoffeaturestomakedeveloperslifeeasier
  • JavaSE8

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  • JavaSE8
  • Majornewfeatures:ModularisationandClosures
  • Moresmallerfeaturestobedefined
  • JavacontinuestogrowandadapttothechangingworldofIT
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SLIDE 61

VielenDankfürIhreAufmerksamkeit!

Wolfgang.Weigend@oracle.com

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SLIDE 62

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SLIDE 63

WirdJava7eingesetzt?

Umfrage aufjava.net:“HaveyoutriedoutJava7yet?”

Yes, and I`m working with it regulary (25%) I`ve experimented with it a bit (21%)

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I plan to get started with Java 7 soon (25%) I`m waiting for a bug fix release (18%) No, and I don´t plan to (11%)

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SLIDE 64

JDK7UpdateReleases

Fehlerbereinigung

  • ProjektentwickeltUpdatesfürJDK7
  • SponsoristdieBuildGroup
  • MailingListelautetjdk7u-dev
  • TechnischeDiskussionzumJDK7UpdatesProjekt
  • ArchivevorhandenfürJuly2011,August2011

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  • ArchivevorhandenfürJuly2011,August2011
  • NachrichtenanalleTeilnehmerverschicken:

jdk7u-dev@openjdk.java.net

  • jdk7u-devSubscription
  • JavaSE7Update2BinarySnapshotReleases
  • ListederÄnderungenimaktuellenJDK7u2Buildb02
  • ProjectFeedbackForumfürJavaSESnapshots
  • ReportaBugoderRequestaFeature
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SLIDE 65

OracleJavaMagazine

  • OnlineInformationenfürJavaTechnologie
  • ZusammenarbeitmitdergesamtenJavaCommunity
  • Oracle'sInvestmentzurStärkungvomJavaTechnologieÖkosystem

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