0
Modularity of the Java
Platform
Martin Toshev
BG JUG mailing list:
https://groups.google.com/forum/#
!forum/bg-jug
Agenda
• Modularity 101
• Modularity on top of the platform: OSGi
• Modularity of the platform: Jigsaw
• OSGi and Jigsaw i...
Modularity 101
Modularity 101
• Standard Java libraries are modules - Hibernate,
log4j and any library you can basically think of …
• Bui...
Modularity 101
• Benefits of modularization:
– smaller modules are typically tested easier than a
monolithic application
–...
Modularity 101
• Benefits of modularization:
– development of the system can be split easier
between teams/developers
– in...
Modularity 101
• The dependency mechanism used by the JDK
introduces a number of problems that modular
systems aim to solv...
Modularity 101
• The dependency mechanism used by the JDK
introduces a number of problems that modular
systems aim to solv...
Modularity 101
• Module systems aim to solve the mentioned
problems and typically provide:
– module management
– module de...
Modularity on top of the
platform: OSGi
Modularity on top of the platform:
OSGi
• OSGi (Open Service Gateway initiave) provides a
specification for module systems...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: An OSGi runtime (module system) makes use of th...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: An OSGi bundle is a just a JAR file that contai...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: The OSGi Core spec defines a layered architectu...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: Bundles may export packages for use by other bu...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: The MANIFEST.MF file of the bundle’s JAR file d...
Modularity on top of the platform:
OSGi
Q: So what is an OSGi runtime ?
A: The runtime may implement extensions based on t...
Modularity on top of the platform:
OSGi
Q: What about Maven support for OSGi bundles ?
Modularity on top of the platform:
OSGi
Q: What about Maven support for OSGi bundles ?
A: Such a support is provided by th...
Modularity on top of the platform:
OSGi
• OSGi continues to evolve …
Live Demo
Modularity on top of the platform: OSGi
Modularity of the platform:
Jigsaw
Modularity of the platform:
Jigsaw
• When speaking of modularity we should also
consider the entire runtime (rt.jar) and t...
Modularity of the platform:
Jigsaw
• The JDK is monolithic …
Modularity of the platform:
Jigsaw
• JDK 8 compact profiles provide smaller versions …
(javac -profile <profile_name> or
m...
Modularity of the platform:
Jigsaw
• The aim of project Jigsaw is to provide a module
system for the Java platform
• Altho...
Modularity of the platform:
Jigsaw
• Modularization of the Java platform is a
significant change that impacts the entire
e...
Modularity of the platform:
Jigsaw
Q: So what is exactly project Jigsaw ?
Modularity of the platform:
Jigsaw
Q: So what is exactly project Jigsaw ?
A: Jigsaw will provide the basis for a Java Modu...
Modularity of the platform:
Jigsaw
Q: So what is exactly project Jigsaw ?
A: Project Jigsaw provides a modularized version...
Modularity of the platform:
Jigsaw
Q: So what is exactly project Jigsaw ?
A: No jre directory exists anymore in the JDK in...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: A collection of Java classes, native libraries and othe...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Jigsaw resolves modules during build and installation.
...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Module can use ("require") other modules and additional...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Module versions are compared using a similar approach a...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can also "require" optional modules - meaning t...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can also "require" local modules - meaning that...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: A module may export packages and classes
module org.bgj...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can explicitly specify which other modules can
...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can logically provide other module names (alias...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can have a single entry point
the main() method...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: Modules can define multiple views
the main() method org...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: A module can declare that it provides a service
module ...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: A module can require a service
module org.bgjug.B {
req...
Modularity of the platform:
Jigsaw
Q: What is a Jigsaw module ?
A: A service can also be required optionally
module org.bg...
Modularity of the platform:
Jigsaw
Q: How are modules compiled ?
Modularity of the platform:
Jigsaw
Q: How are modules compiled ?
A: The javac compiler is extended with a ModulePath - the...
Modularity of the platform:
Jigsaw
Q: How are modules managed ?
Modularity of the platform:
Jigsaw
Q: How are modules managed ?
A: Modules can be added to module libraries. Various tools...
Modularity of the platform:
Jigsaw
Q: So why not adopt OSGi (at least the module layer) for
modularization of the Java pla...
Modularity of the platform:
Jigsaw
Q: So why not adopt OSGi (at least the module layer) for
modularization of the Java pla...
Modularity of the platform:
Jigsaw
Q: So why not adopt OSGi (at least the module layer) for
modularization of the Java pla...
Modularity of the platform:
Jigsaw
Q: What about IDE support for Jigsaw module development ?
Modularity of the platform:
Jigsaw
Q: What about IDE support for Jigsaw module development ?
A: It is still an early stage...
Modularity of the platform:
Jigsaw
Q: What about Maven support for Jigsaw module development ?
Modularity of the platform:
Jigsaw
Q: What about Maven support for Jigsaw module development ?
A: Still at a very early st...
Modularity of the platform:
Jigsaw
Q: What about Maven support for Jigsaw module development ?
A: According the Peter Krie...
Live Demo
Modularity of the platform: Jigsaw
OSGi and Jigsaw interoperability:
Penrose
OSGi and Jigsaw interoperability:
Penrose
• When speaking of JDK modules we should
consider interoperability with existing...
OSGi and Jigsaw interoperability:
Penrose
• Penrose is still in early stage of development …
OSGi and Jigsaw interoperability:
Penrose
• Penrose goals:
– ensuring OSGi frameworks run unmodified in an
Jigsaw-enabled ...
OSGi and Jigsaw interoperability:
Penrose
• Penrose goals:
– mapping Jigsaw metadata to OSGi metadata
– resolve Jigsaw mod...
OSGi and Jigsaw interoperability:
Penrose
• Since module-info.java is compiled to module-
info.class this implies that cla...
OSGi and Jigsaw interoperability:
Penrose
MANIFEST.MF (OSGi)
module-info.java (Jigsaw)
module org.bgjug @ 1.0 {
exports or...
Summary
Q: Projects Jigsaw/Penrose - when ?
Summary
Q: Projects Jigsaw/Penrose - when ?
A: Maybe when the Armagedon comes …
Summary
Q: Projects Jigsaw/Penrose - when ?
A: Unless you …
… discuss:
http://mail.openjdk.java.net/mailman/listinfo/penro...
Q&A
Thank you
Bulgarian JUG mailing list:
https://groups.google.com/forum/#!forum/bg-jug
References
OSGi Alliance
http://www.osgi.org/Main/HomePage
Jigsaw Project
http://openjdk.java.net/projects/jigsaw/
Penrose...
References
Modularity - what is it ?
http://www.infoq.com/articles/modular-java-
what-is-it/
Java modularity - why ?
http:...
References
Java Module System Requirements
http://openjdk.java.net/projects/jigsaw/doc/draf
t-java-module-system-requireme...
References
Project Jigsaw: Late for the train
http://mreinhold.org/blog/late-for-the-train-qa
Unbearable lightness of Jigs...
References
Java Modularity - OSGi and Project Jigsaw
http://techdistrict.kirkk.com/2009/06/12/java-
modularity-osgi-and-pr...
References
JavaOne 2013: The Modular Java Platform and Project
Jigsaw
http://parleys.com/play/52549d02e4b0a43ac12
124be/ab...
Upcoming SlideShare
Loading in...5
×

Modularity of the Java Platform (OSGi, Jigsaw and Penrose)

2,738

Published on

Seminar "Modularity of the Java Platform" of the Bulgarian Java User Group.
Topics of the seminar:
Modularity 101
Modularity on top of the platform: OSGi
Modularity of the platform: Jigsaw
OSGi and Jigsaw interoperability: Penrose

Published in: Technology, Education
0 Comments
4 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,738
On Slideshare
0
From Embeds
0
Number of Embeds
4
Actions
Shares
0
Downloads
56
Comments
0
Likes
4
Embeds 0
No embeds

No notes for slide
  • Some people argue that Java libraries are not modules since they do not provide encapsulation (such as classes and packages).
  • Evolution of modules in the default classloading mechanism supported by the Java platform may cause the so called "JAR hell" problem when conflicting versions of the same library are present on the classpath or required by different libraries. In order to evolve libraries in a compatible way using the default classloading mechanism on must design libraries with backward/forward compatibility in mind.
  • Evolution of modules in the default classloading mechanism supported by the Java platform may cause the so called "JAR hell" problem when conflicting versions of the same library are present on the classpath or required by different libraries. In order to evolve libraries in a compatible way using the default classloading mechanism on must design libraries with backward/forward compatibility in mind.
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • The module can use an enhanced version of java.util.ServiceLoader to load the service
  • The module can use an enhanced version of java.util.ServiceLoader to load the service
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • multiple packages with the same name can be defined in different modules in that manner (and they are merged when modules are loaded)
    the optional modules may be explicitly required to "permit" the requiring module in the future
  • The only benefit in Jigsaw according to Peter Kriens:
    The only reason I can think of is that is easier for the module system providers to program. In the Jigsaw model traversing the dependencies is as easy as taking the module name + version, combining it with a repository URL, doing some string juggling and using the result as a URL to your module. 
  • Transcript of "Modularity of the Java Platform (OSGi, Jigsaw and Penrose)"

    1. 1. Modularity of the Java Platform Martin Toshev
    2. 2. BG JUG mailing list: https://groups.google.com/forum/# !forum/bg-jug
    3. 3. Agenda • Modularity 101 • Modularity on top of the platform: OSGi • Modularity of the platform: Jigsaw • OSGi and Jigsaw interoperability: Penrose
    4. 4. Modularity 101
    5. 5. Modularity 101 • Standard Java libraries are modules - Hibernate, log4j and any library you can basically think of … • Build systems like Maven provide transparent management of modules
    6. 6. Modularity 101 • Benefits of modularization: – smaller modules are typically tested easier than a monolithic application – allows for easier evolution of the system - modules evolve independently
    7. 7. Modularity 101 • Benefits of modularization: – development of the system can be split easier between teams/developers – increased maintainability of separate modules
    8. 8. Modularity 101 • The dependency mechanism used by the JDK introduces a number of problems that modular systems aim to solve: – The "JAR hell" problem caused by shortcomings of the classloading process
    9. 9. Modularity 101 • The dependency mechanism used by the JDK introduces a number of problems that modular systems aim to solve: – The lack of dynamicity in managing dependent modules – The lack of loose coupling between modules
    10. 10. Modularity 101 • Module systems aim to solve the mentioned problems and typically provide: – module management – module deployment – versioning – dependency management – module repositories – configuration management
    11. 11. Modularity on top of the platform: OSGi
    12. 12. Modularity on top of the platform: OSGi • OSGi (Open Service Gateway initiave) provides a specification for module systems implemented in Java • It is introduced as JSR 8 and JSR 291 to the Java platform
    13. 13. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ?
    14. 14. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: An OSGi runtime (module system) makes use of the Java classloading mechanism in order to implement a container for modular units (bundles) and is based on the OSGi spec - a series of standards by the OSGi Alliance. Many application servers are implemented using OSGi as a basis - it is also used in systems from a diversity of areas
    15. 15. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: An OSGi bundle is a just a JAR file that contains source code, bundle metadata and resources. A bundle may provide various services and components to the OSGi runtime. An OSGi runtime allows for bundles to be installed, started, stopped, updated and uninstalled without requiring a reboot
    16. 16. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: The OSGi Core spec defines a layered architecture that determines what is supported by the runtime – each layer defines a particular functionality supported by the runtime and the bundles OSGi logical units:  bundles  services  services registry  life-cycle  modules  security  execution environment OSGi logical layers:
    17. 17. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: Bundles may export packages for use by other bundles or import packages exported by other bundles - this dependency mechanism is referred to as wire protocol and is provided by the Module layer of OSGi. Bundles may publish services to the runtime and use already published services from the runtime – this dependency mechanism is provided by the Service layer of OSGI.
    18. 18. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: The MANIFEST.MF file of the bundle’s JAR file describes the metadata of the bundle Manifest-Version: 1.0 Bundle-ManifestVersion: 2 Bundle-Name: Sample Bundle-SymbolicName: com.sample Bundle-Version: 1.0.0.qualifier Bundle-Activator: sample.Activator Bundle-Vendor: QIVICON Require-Bundle: org.eclipse.smarthome.core, com.qivicon.extensions Bundle-RequiredExecutionEnvironment: JavaSE-1.7 Service-Component: OSGI-INF/service.xml Import-Package: com.qivicon.services.hdm;version="3.0.0“ Export-Package: com.sample.utils
    19. 19. Modularity on top of the platform: OSGi Q: So what is an OSGi runtime ? A: The runtime may implement extensions based on the OSGi Compendium spec that extends the OSGi Core spec. These could be:  remote services  log service  HTTP service  device access service  configuration admin  metatype service  preferences service  user admin  wire admin  DMT admin service  IO connector service  provisioning service  UPnP device service  configuration admin  declarative services  event admin service  deployment admin  XML parser service  monitoring service  others
    20. 20. Modularity on top of the platform: OSGi Q: What about Maven support for OSGi bundles ?
    21. 21. Modularity on top of the platform: OSGi Q: What about Maven support for OSGi bundles ? A: Such a support is provided by the Tycho Maven plug-ins that provide support for packaging types, target platform definitions, interoperability with the Maven dependency mechanism and so on …
    22. 22. Modularity on top of the platform: OSGi • OSGi continues to evolve …
    23. 23. Live Demo Modularity on top of the platform: OSGi
    24. 24. Modularity of the platform: Jigsaw
    25. 25. Modularity of the platform: Jigsaw • When speaking of modularity we should also consider the entire runtime (rt.jar) and the JDK core libraries … • … and built-in support for improved "OSGi-like" modules in the Java platform
    26. 26. Modularity of the platform: Jigsaw • The JDK is monolithic …
    27. 27. Modularity of the platform: Jigsaw • JDK 8 compact profiles provide smaller versions … (javac -profile <profile_name> or make profiles for an OpenJDK build) compact 1 compact 2 compact 3
    28. 28. Modularity of the platform: Jigsaw • The aim of project Jigsaw is to provide a module system for the Java platform • Although deferred to JDK 9 some additional effort such as Compact Profiles and removed/ deprecated inter-library dependencies have been introduced in JDK8 as an intermediate solution
    29. 29. Modularity of the platform: Jigsaw • Modularization of the Java platform is a significant change that impacts the entire ecosystem - may even break existing projects
    30. 30. Modularity of the platform: Jigsaw Q: So what is exactly project Jigsaw ?
    31. 31. Modularity of the platform: Jigsaw Q: So what is exactly project Jigsaw ? A: Jigsaw will provide the basis for a Java Module System JSR
    32. 32. Modularity of the platform: Jigsaw Q: So what is exactly project Jigsaw ? A: Project Jigsaw provides a modularized version of JDK along with additional tools and language support for creating Jigsaw modules. Currently early-access builds provide two types of JDK:  JDK modules image - all components are preinstalled as modules  JDK base image + jmod packages - base JDK installation along with additional Jigsaw modules of the JDK that can be installed on-demand using the jmod tool
    33. 33. Modularity of the platform: Jigsaw Q: So what is exactly project Jigsaw ? A: No jre directory exists anymore in the JDK installation, rt.jar and tools.jar no longer exist. Modular JDK must be compatible with existing applications to a greater extend. Legacy applications are expected to run on a Jigsaw JDK if: – they don't depend upon the internal structure of the JDK/JRE – they use only supported APIs
    34. 34. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ?
    35. 35. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: A collection of Java classes, native libraries and other resources along with metadata that provides name and version of the module and dependencies on other modules
    36. 36. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Jigsaw resolves modules during build and installation. Jigsaw has no dynamics, no module lifecycle. The module system assumes the existence of a foundational module named java.base
    37. 37. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Module can use ("require") other modules and additionally specify version or version ranges for the module dependency - modules are loaded with different module classloaders module org.bgjug.A @ 1.0 { requires org.bgjug.B @ [2.0, 3.0); } module org.bgjug.A { requires org.bgjug.B @ >= 1.0; requires org.bgjug.C @ < 2.0; }
    38. 38. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Module versions are compared using a similar approach as the one used for Debian package versions …
    39. 39. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can also "require" optional modules - meaning that compilation succeeds even if the required module is missing module org.bgjug.A { requires optional jdk-corba@8-ea; }
    40. 40. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can also "require" local modules - meaning that the local module is a kind of a "mixin" - it is loaded in the same classloader as the requiring module module org.bgjug.A @ 1.0 { requires local org.bgjug.B @ [2.0, 3.0); }
    41. 41. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: A module may export packages and classes module org.bgjug.A @ 1.0 { requires org.bgjug.B @ [2.0, 3.0); exports org.bgjug.A.seminar.Sample; exports org.bgjug.A.seminar.samples.*; }
    42. 42. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can explicitly specify which other modules can "require" them module org.bgjug.A @ 2.0 { exports org.bgjug.A.seminar; permits org.bgjug.B; }
    43. 43. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can logically provide other module names (aliases): module com.bgjug.A @ 1.0 { provides com.bgjug.First @ 2.0; }
    44. 44. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can have a single entry point the main() method org.bgjug.A.Main is called when invoking: java -m org.bgjug.A module org.bgjug.A @ 1.0 { permits org.bgjug.B; class org.bgjug.A.Main; }
    45. 45. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: Modules can define multiple views the main() method org.bgjug.A.Main is called when invoking: java -m org.bgjug.A module org.bgjug.A { exports org.bgjug.A.seminar; view org.bgjug.internal.view { permits org.bgjug.B } }
    46. 46. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: A module can declare that it provides a service module org.bgjug.A { provides service org.bgjug.A.external.TestService with org.bgjug.A.external.TestServiceImpl; }
    47. 47. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: A module can require a service module org.bgjug.B { requires service org.bgjug.A.external.TestService }
    48. 48. Modularity of the platform: Jigsaw Q: What is a Jigsaw module ? A: A service can also be required optionally module org.bgjug.B{ requires optional service org.bgjug.A.TestService; }
    49. 49. Modularity of the platform: Jigsaw Q: How are modules compiled ?
    50. 50. Modularity of the platform: Jigsaw Q: How are modules compiled ? A: The javac compiler is extended with a ModulePath - the equivalent of ClassPath but for module dependencies (-modulepath option) For javac the -d option (that specifies the output directory): – outputs to legacy single-module structure if ClassPath is set – outputs to multi-module structure if ModulePath is set
    51. 51. Modularity of the platform: Jigsaw Q: How are modules managed ?
    52. 52. Modularity of the platform: Jigsaw Q: How are modules managed ? A: Modules can be added to module libraries. Various tools are added to support creation of modules, module libraries and module repositories and packaging of artifacts: – jmod - for managing modules and module libraries – jpkg - for packaging modules (uses pack200 compression)
    53. 53. Modularity of the platform: Jigsaw Q: So why not adopt OSGi (at least the module layer) for modularization of the Java platform ?
    54. 54. Modularity of the platform: Jigsaw Q: So why not adopt OSGi (at least the module layer) for modularization of the Java platform ? A: As chief architect of the Java platform Mark Reinhold states: The OSGI module layer is not operative at compile time - it addresses modularity only during packaging, deployment and execution. It is also strictly build on top of the platform so it cannot be used to modularize it. For compile-time resolution of OSGi dependencies during development IDEs (such as Eclipse) and build tooling (such as Maven) provide a mechanism for specifying a target platform which is collection of bundles used to provide compile-time dependencies
    55. 55. Modularity of the platform: Jigsaw Q: So why not adopt OSGi (at least the module layer) for modularization of the Java platform ? A: However - according to Peter Kriens (former technical director at the OSGi Alliance and one of the key drivers behind the OSGi spec) Jigsaw is not typically needed an will introduce burden to the platform and modules can be introduced much easier: The only thing we need to add to the existing system is versioning information on the package and record this version in the class file
    56. 56. Modularity of the platform: Jigsaw Q: What about IDE support for Jigsaw module development ?
    57. 57. Modularity of the platform: Jigsaw Q: What about IDE support for Jigsaw module development ? A: It is still an early stage to consider possible IDE support - IDE vendors outline use cases for Jigsaw usage in order to consider how to extend their IDEs with Jigsaw support (valid mostly for NetBeans - Eclipse and IntelliJ are still idle). However - according to Peter Kriens the structure of a JDK module (especially the module-info.java file) will increase effort needed to support modules in the various IDEs and build tools
    58. 58. Modularity of the platform: Jigsaw Q: What about Maven support for Jigsaw module development ?
    59. 59. Modularity of the platform: Jigsaw Q: What about Maven support for Jigsaw module development ? A: Still at a very early stage of discussion - but most probably Maven will provide build-in support for Jigsaw modules and module dependency resolution from upstream Jigsaw repositories
    60. 60. Modularity of the platform: Jigsaw Q: What about Maven support for Jigsaw module development ? A: According the Peter Kriens: And not to forget the build tools, they will start having to interpret the module-info file and link to the appropriate module system to find their class path. Today, a build tool tells the compiler its class path, in the future it would first have to compile or interpret the Java file. This alone will probably kill 90% of the ant scripts because the class path is used in other places then compiling. Also maven will have to start to interact with this
    61. 61. Live Demo Modularity of the platform: Jigsaw
    62. 62. OSGi and Jigsaw interoperability: Penrose
    63. 63. OSGi and Jigsaw interoperability: Penrose • When speaking of JDK modules we should consider interoperability with existing module systems such as OSGi • The purpose of project Penrose is to explore interoperability between OSGi and Jigsaw
    64. 64. OSGi and Jigsaw interoperability: Penrose • Penrose is still in early stage of development …
    65. 65. OSGi and Jigsaw interoperability: Penrose • Penrose goals: – ensuring OSGi frameworks run unmodified in an Jigsaw-enabled runtime – create modules/bundles that have both OSGi and Jigsaw metadata in them – Jigsaw metadata can be extended with OSGi concepts – extend OSGi to read Jigsaw module info
    66. 66. OSGi and Jigsaw interoperability: Penrose • Penrose goals: – mapping Jigsaw metadata to OSGi metadata – resolve Jigsaw modules in an OSGi runtime – enhance OSGi to use Jigsaw repositories and APIs – more cross delegation between the two systems …
    67. 67. OSGi and Jigsaw interoperability: Penrose • Since module-info.java is compiled to module- info.class this implies that class file must be parsed in order to read metadata • Penrose proposes a simpler JSON format (module-info.json) that can be used to generate both Jigsaw and OSGi metadata
    68. 68. OSGi and Jigsaw interoperability: Penrose MANIFEST.MF (OSGi) module-info.java (Jigsaw) module org.bgjug @ 1.0 { exports org.bgjug.external; } Manifest-Version: 1.0 Bundle-ManifestVersion: 2 Bundle-Name: org.bgjug Bundle-SymbolicName: org.bgjug Bundle-RequiredExecutionEnvironment: JavaSE-1.7 Export-Package: org.bgjug.external;version="1.0.0" module-info.json (Penrose) "module" : { "name" : "org.bgjug", "version": 1.0, "exports" : [{ "name" : "org.bgjug.external", "org.osgi.version" : "1.0.0" }] } module-info.json (Penrose)
    69. 69. Summary Q: Projects Jigsaw/Penrose - when ?
    70. 70. Summary Q: Projects Jigsaw/Penrose - when ? A: Maybe when the Armagedon comes …
    71. 71. Summary Q: Projects Jigsaw/Penrose - when ? A: Unless you … … discuss: http://mail.openjdk.java.net/mailman/listinfo/penrose-dev http://mail.openjdk.java.net/mailman/listinfo/jigsaw-dev http://mail.openjdk.java.net/mailman/listinfo/penrose-discuss … and code: http://hg.openjdk.java.net/jigsaw http://hg.openjdk.java.net/penrose
    72. 72. Q&A Thank you Bulgarian JUG mailing list: https://groups.google.com/forum/#!forum/bg-jug
    73. 73. References OSGi Alliance http://www.osgi.org/Main/HomePage Jigsaw Project http://openjdk.java.net/projects/jigsaw/ Penrose Project http://openjdk.java.net/projects/penrose/
    74. 74. References Modularity - what is it ? http://www.infoq.com/articles/modular-java- what-is-it/ Java modularity - why ? http://java.dzone.com/articles/java-modularity- 2-why Java JAR hell problem http://en.wikipedia.org/wiki/Java_Classloader#JA R_hell
    75. 75. References Java Module System Requirements http://openjdk.java.net/projects/jigsaw/doc/draf t-java-module-system-requirements-12 Project Jigsaw: The Big Picture http://cr.openjdk.java.net/~mr/jigsaw/notes/jigs aw-big-picture-01 Java 8 Modules Jigsaw and OSGi http://www.slideshare.net/mfrancis/java-8- modules-jigsaw-and-osgi-neil-bartlett
    76. 76. References Project Jigsaw: Late for the train http://mreinhold.org/blog/late-for-the-train-qa Unbearable lightness of Jigsaw http://blog.osgi.org/2011/05/unbearable- lightness-of-jigsaw.html Netbeans discussion on Jigsaw http://wiki.netbeans.org/Jigsaw
    77. 77. References Java Modularity - OSGi and Project Jigsaw http://techdistrict.kirkk.com/2009/06/12/java- modularity-osgi-and-project-jigsaw/ The Modular Java Platform & Project Jigsaw http://www.jfokus.se/jfokus14/preso/Jigsaw.pdf JAX 2013: A Project Jigsaw primer http://jaxenter.com/a-project-jigsaw-primer- 50029.html
    78. 78. References JavaOne 2013: The Modular Java Platform and Project Jigsaw http://parleys.com/play/52549d02e4b0a43ac12 124be/about OpenJDK Penrose JavaOne 2012 http://www.slideshare.net/bosschaert/open-jdk- penrose-javaone-2012
    1. A particular slide catching your eye?

      Clipping is a handy way to collect important slides you want to go back to later.

    ×