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Jigsaw est prêt à tuer le

classpath@AlexisHassler - #devfestnantes

"Classpath is dead!"

Mark ReinholdJavaOne 2009

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Classpath Classloader

SuccessionJigsaw

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Alexis Hassler

Développeur

Formateur

Indépendant

Fondateur

Préparateur de

Classpath

https://www.fickr.com/photos/summonedbyfells/15007676965

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String hello = "Salut à vous tous les zazous";

Chercher les classes

CLASSPATH

Hello var = new Hello();

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-classpath

java -cp hello-lib.jar HelloWorld

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Erreurs

java.lang.NoClassDefFoundError

java.lang.ClassNotFoundException

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Class Loader

https://www.fickr.com/photos/15574096@N00/12119344725/

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java.lang.ClassLoader

loadClass(String name) : Class<?>

getResource(String name) : URLgetResourceAsStream(String name) : InputStream

getParent() : ClassLoader

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Classloader

sun.misc.Launcher$AppClassLoader CLASSPATH

Hello.class.getClassLoader()

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Classloader

null

Hello.class.getClassLoader()

.getClass().getClassLoader()

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Bootstrap Classloader

BootstrapClassLoader

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Délégation

BootstrapClassLoader

Parent frst

System ClassLoader

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Délégation

System ClassLoader

java -cp hello-lib.jar ...

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bootclasspath

java -Xbootclasspath/p:hello-lib.jar ...

java -Xbootclasspath:hello-rt.jar ...

java -Xbootclasspath/a:hello-lib.jar ...

BootstrapClassLoader

https://github.com/hasalex/classpath-demo

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DémonstrationBootstrapClassLoader

java -cp example.jar fr.sewatech.classpath.Count

System ClassLoader

java.lang.Integer

example.jar

java.lang.Integer

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example.jar

Démonstration

java  -Xbootclasspath/p:example.jar  fr.sewatech.classpath.Count

BootstrapClassLoader

java.lang.Integer

java.lang.Integer

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URLClassloader

java.net.URLClassLoader

sun.misc.Launcher$AppClassLoader

URLURLURL

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URLClassloader

System ClassLoader

Bootstrap ClassLoader

URL ClassLoader

URL ClassLoader

URL ClassLoader

Parentfrst

Parentfrst

Parentfrst

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DIY Classloader

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Usages

Application Servers JRebel Javassist, CGLib,...

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Tomcat

System

Bootstrap

Common

Webapp1

Webapp2

Webapp3

Local First

message-launcher

message-main

message-common

message-printer

message-service

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Démonstration

message-launcher

message-common

message-printer

message-service

message-service

System ClassLoader ParentFirst ClassLoader

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Démonstration

message-launcher

message-common

message-printer

message-service

message-service

System ClassLoader LocalFirst ClassLoader

https://www.fickr.com/photos/delete08/5971235700/

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Dépendances

Maven, Gradle,...

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Dépendances

Classpath

https://github.com/hasalex/classpath-demo

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Démonstration

slf4j-api 1.5.11

slf4j-api 1.7.2

message-launcher

message-main

message-common

message-printer

message-service

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Granularité

SécuritéApache commons-collections

https://foxglovesecurity.com/

Succession

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Modularité

Dépendance Exposition

Lecture

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1999

Java embarquéJava SEJava serveur

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Bundle-Name = Hello Service

Bundle-SymbolicName = hello-service

Bundle-Description = Hello Service Bundle

Bundle-Version = 1.0.1

Export-Package = fr.sewatech.classpath

Import-Package = fr.sewatech.classpath.print;version=1.3

OSGi

Bundle

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OSGi

OS + Hardware

Java Runtime

Module

Life Cycle Services

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JBoss Modules

java -jar jboss-modules.jar -mp path/to/modules

my.main.module.name

Base de JBoss OSGi

Java SE

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JBoss Modules

module.xml

resource dependency slot

dependency slot

dependency slot

name slot

resource

resource

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Jigsaw

9 (2016)8 (2012)

(2017)

Projet

Intégré au JDK 7 (2008)

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Jigsaw

Modularité du JDK

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Jigsaw

Modularité des applications// module-info.java

module message.service {

requires java.xml.bind;

requires message.common;

exports fr.sewatech.message;

}

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Jigsaw

Compilation

javac --module-path modules \

-d target/classes/ \

$(find src/main/java/ -name "*.java")

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Jigsaw

Exécution

java --module-path jigsaw-modules \

-m misc.examples/fr.sewatech.example.Main

https://github.com/hasalex/classpath-demo

Jigsaw ++

https://www.fickr.com/photos/intvgene/370973576

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Classpath mode

java -classpath lib/* fr.sewatech.example.Main

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Modular JDK

rt.jar tools.jar

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Modular JDK

https://github.com/hasalex/classpath-demo

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Dependencies

module message.service {

requires message.printer;

requires slf4j.api;

}

module message.printer {

requires transitive message.common;

}

message.printer

message.service

message.common

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module message.service {

requires message.printer;

requires slf4j.api;

}

Dependencies

Automatic modules slf4j-api-1.5.2.

slf4j.api

message.service

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Dependencies

Classpath

message.common

message.printer

unnamed

message.service

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Dependencies

module message.service @ 1.0 {

requires message.printer @ 1.0;

requires slf4j.api @ 1.7;

}

Module version

https://github.com/hasalex/classpath-demo

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Exports

Accessibilitypublicprotectedpackageprivate

inside a module

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Exports

Accessibilitypublic for other modules

module message.service {

exports fr.sewatech.message;

}

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Exports

Accessibilitypublic for some modules

module java.base {

exports sun.reflect to

java.logging,

java.sql,

jdk.scripting.nashorn;

}

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field.setAccessible(true);

Exports

java.lang.reflect.InaccessibleObjectException

Refection

module message.service {

exports private java.security;

}

https://github.com/hasalex/classpath-demo

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Classloader

java.net.URLClassLoader FLTMClassLoader

java.lang.ClassLoader

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BootClassLoader

bootclasspath

java -Xbootclasspath/p:hello-lib.jar ...

java -Xbootclasspath:hello-rt.jar ...

java -Xbootclasspath/a:hello-lib.jar ...

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Patch

Compile

Run

javac -Xmodule:java.base \

-d ../patch-classes \

src/java/lang/Integer.java

java --patch-module java.base=patch.jar \

--module-path jigsaw-modules \

-m misc.examples

https://github.com/hasalex/classpath-demo

Jigsaw ++++

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Aller plus haw avec Jigsaw

Service Providers / Loaders

Layers : versioning

jlink : custom JRE

jdeps : migration

...

Quand ?

https://www.fickr.com/photos/mars_/18189674562/

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Planning

Java SE 9

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Planning

Outils ?Maven, Gradle, IDE

Livrairies ?SLF4J, Guava,...

Frameworks ?Spring, Hibernate,...

Runtimes ?Java EE, Tomcat,...Hadoop,...

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Essayer...

https://jdk9.java.net/download/ Exécutable d'installation

https://jdk9.java.net/jigsaw/ ArchiveDernières évolutions de Jigsaw

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Apprendre +

JavaOnehttp://openjdk.java.net/projects/jigsaw/talks/

Quick-Start Guidehttp://openjdk.java.net/projects/jigsaw/quick-start

The State of the Module Systemhttp://openjdk.java.net/projects/jigsaw/spec/sotms/

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module-path is born

classpath is NOT dead

Conclusion

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https://www.sewatech.fr

@AlexisHassler

http://alexis-hassler.com

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