Modular Applications with OSGi on Apache Karaf

Ioan Eugen Stan@ieugen222

stan.ieugen@gmail.com

About me● IT Consultant (Java, Architecture)● Open Source Hacker● Web: http://ieugen.ro/● http://github.com/ieugen● @ieugen222

Agenda● Problem statement● Short intro to OSGi● Apache Karaf and OSGi universe● Building an App

https://github.com/ieugen/java2days-2014-osgi-karaf

Modularity is a big issue● Deals with software complexity over

time● Jigsaw - Java started from JDK-7 (start

2009)● Has many aspects: deployment,

management, runtime

Why modularity?● Reduce complexity● Allow parallel development● Improve component re-usability● Upgrade proof systems

When Applications can Roam Freely, P. Kriens - http://slideplayer.us/slide/732791/

A solution for Java modularity?Jigsaw was delayed again (does not address dynamism)

Try OSGi – the de facto standard for Java modularity

OSGi – overview● Modular system for Java/JVM● Service platform● Dynamic component model

http://www.slideshare.net/mfrancis/osgi-technology-value-proposition-december-2013

OSGi Benefits● Reduced Complexity● Promotes Reuse● Real World – things appear/disappear● Dynamic updates

HardwareOperating SystemJava Virtual Machine

ModulesLife cycle

Service registryServices

Application / Bundles

Sec

uri

ty

http://en.wikipedia.org/wiki/OSGi

OSGi Service Gateway Architecture

http://en.wikipedia.org/wiki/OSGi

OSGi Architecture (2)

Bundle 1 Bundle 2 Bundle n

System Services

e.g. Java ME CDC, SE, EE

e.g. Windows, Linux VxWorks, QNX

C/C++

OSGi Framework

Java Runtime Environment

Operating System

Hardware

Driv

ers

Plat

form

Serv

er

JNI

Apache KarafApache Karaf is a small OSGi based runtime which provides a lightweight container onto which various components and applications can be deployed.

http://karaf.apache.org/

Karaf Architecture

Features● Hot deployment of bundles● Dynamic configuration● Provisioning of applications ● Native OS integration● Remote Access (SSH, Web)● ...

Projects● OPS4j - https://github.com/ops4j● OSGi JAX-RS Connector

https://github.com/hstaudacher/osgi-jax-rs-connector

Demo time

Thank you.Time for questions.