What is being a good developer? How can we work to become better?

TL;DR

  • future of the Java ecosystem
  • JavaSE, Java EE workshops at Devoxx UK 2015
  • OpenJDK and JSRs
  • extraordinary developers
  • hands-on sessions, hackdays and panel
  • learn, collaborate and share
  • developer communities, JUG leaders, and corporate participations
  • thought leaders and tomorrow’s leaders of Java related topics
  • agenda, costs, tickets and discount codes

The Adopt team are running workshops at Devoxx UK next month that will help to answer the questions posed above. Why should you get along to a workshop? Well, here’s an imagined conversation between you and the Adopt team to explain. The Adopt Team are an ever growing community from various parts of the developer community, mainly the JUGs worldwide, members of the JCP, developers, evangelists and technical representatives of various companies supporting and extending the Java ecosystem via the JCP, Adopt-a-JSR  and Adopt OpenJDK programs.


You: I hear that there are a number of workshops going to be held during the first day of Devoxx UK 2015. What are these?

Adopt team: Yes, you heard right, we have a whole day (Wednesday) dedicated to it. In brief, the adopt team at Devoxx UK this year is comprised of experienced developers and leaders of various Java SE and Java EE topics i.e. OpenJDK, and a number of JSRs. These include members of the JCP as well. The topics range from learning how to build OpenJDK, working with devops tools, quality analysis tools, contributing and working with JSRs (guided by spec leads of the respective JSRs). Learning how to run a hackday if you want to start your own community where you are. And towards the end of the session you can get answers to the questions you have been pondering upon before or at the conference.

Have a look at the agenda to find out more.


You: Apart from OpenJDK, can you name some JSRs we will be involved with?

Adopt team: Good questions. We will have amongst us spec leads from the various JSRs:

  • JSR 363, Units of Measurement API – Leonardo Lima
  • JSR JSR 365, CDI 2.0 – Antoine Sabot-Durand
  • Java EE 8, and some of the proposed component JSRs, including JSR 371 MVC, the Security JSR, and JMS – David Delabassee

You: I’m a busy person, and there’s lots on at Devoxx. Why would I spend time at these workshops rather than doing something else? What do I gain from it?

Adopt team: Depending the workshop you attend you attend and participate in, the benefits can be any or all of these:

  • a great opportunity to feedback on tomorrow’s technology
  • learn and contribute to these technologies even before they are released
  • contributing to the future of the Java / Java platform
  • learn how to build your own Java / JVM platform
  • learn new technologies and improve your confidence,; including automation, code-coverage, testing technologies etc.
  • be able to make contact with and talk to the developers who are leading one or more of the technologies
  • be able to share with your own local user group / community the things you learn in the workshop
  • become a part of the adopt community and keep in touch about current and future developments, hackdays and other workshops

Contributions can be in any form, from as simple as speaking about it to another colleague, writing a post about it, or even mentioning it on a relevant mailing list.


You: So who is this aimed at? Who is your target audience?

Adopt team: Our primary goal is to propagate the know-how and experience various Java User Group leaders all across the globe, but we see everyone else benefiting from it as well: students, professionals, tech leads, devops, trainers, experts, etc…


You: What if my company wishes to be involved? Can you give me examples of companies who are already involved in this program?

Adopt team: Yes, companies, user groups, dev communities are all welcome. A number of companies are involved with the adoption program including: Oracle, IBM, RedHat, SAP, Google, Twitter, Goldman Sachs, Credit Suisse, among many others.


You: Can I or my company make contributions to any of the projects?

Adopt team: Yes, of course, that’s the whole point. One of the reasons is not just spread awareness and know-how of the upcoming technologies in the Java/JVM world but also to show how you can do it yourself. The topics and subtopics are numerous and this is an opportunity to pick one and lead it. You can drive these technologies with the help other community members, helping move your vision forward. Come along to a workshop to find out more!


You: So how much more does it cost me or my company if I have to attend these workshops?

Adopt team: Have a look at the ticket prices for the university days and the combi-tickets. You can also take advantage of special discount codes from us to get further discounts on the final ticket prices (ranging from 10 to 20%).


You:  What do we take along with us to be able to participate in the workshops ?

Adopt team: Bring along a laptop and a fresh mind to absorb all the knowledge and experience we have to share.


You: I hear this theme ‘The Extraordinary…. what is it about, tell me more” Why is this post so titled?

Adopt team: Another good question: to know more about the theme have a look at this http://www.devoxx.co.uk/2015/03/whats-theme/.

Good developers do what every developer does and more. They come to conferences like Devoxx, attend local dev events and talks, participate in workshops similar to the ones this post speaks about and then go out and share many of those things with other fellow developers in the form of blog posts, code snippets or even local community presentations.


You: What about those who can’t get to the workshop. How can they find out more and get involved?

Adopt team: These three websites are a great starting point to get to know more about the adopt programs: http://www.jcp.org, http://adoptopenjdk.java.net and http://adoptajsr.java.net/, but if you are based in London, the LJC organises a hackday every month, see http://www.meetup.com/Londonjavacommunity/events/222368734/, in the past developers from outside London and even outside the UK have visited the day-long hackdays.


You:  So tell me how did this come about? Who do you credit the initiative to?

Adopt team: Nice question: credit must go to where it is due. Thanks to the support from the JCP organisation i.e. Heather VanCura and Mark Hazell for making it happen at Devoxx UK this year. Not forgetting that any event like this one isn’t possible without the help of local and worldwide developer communities, with the likes of London Java Community (@LJCJug), continuously supporting good developer endeavours.


You: How to get the code?

Adopt team: That’s an important question, get in touch with Heather VanCura (heather@jcp.org) or Mark Hazell (mark.hazell@devoxx.co.uk) and they should help you sort out a discount code for you, but hurry are they will get exhausted soon.


How is Java / JVM built ? Adopt OpenJDK is your answer!

Introduction & history
As some of you may already know, starting with Java 7, OpenJDK is the Reference Implementation (RI) to Java. The below time line gives you an idea about the history of OpenJDK:
OpenJDK history (2006 till date)
If you have wondered about the JDK or JRE binaries that you download from vendors like Oracle, Red Hat, etcetera, then the clue is that these all stem from OpenJDK. Each vendor then adds some extra artefacts that are not open source yet due to security, proprietary or other reasons.


What is OpenJDK made of ?
OpenJDK is made up of a number of repositories, namely corba, hotspot, jaxp, jaxws, jdk, langtools, and nashorn. Between OpenjJDK8 and OpenJDK9 there have been no new repositories introduced, but lots of new changes and restructuring, primarily due to Jigsaw – the modularisation of Java itself [2] [3] [4] [5].
repo composition, language breakdown (metrics are estimated)
Recent history
OpenJDK Build Benchmarks – build-infra (Nov 2011) by Fredrik Öhrström, ex-Oracle, OpenJDK hero!

Fredrik Öhrström visited the LJC [16] in November 2011 where he showed us how to build OpenJDK on the three major platforms, and also distributed a four page leaflet with the benchmarks of the various components and how long they took to build. The new build system and the new makefiles are a result of the build system being re-written (build-infra).


Below are screen-shots of the leaflets, a good reference to compare our journey:

How has Java the language and platform built over the years ?

Java is built by bootstrapping an older (previous) version of Java – i.e. Java is built using Java itself as its building block. Where older components are put together to create a new component which in the next phase becomes the building block. A good example of bootstrapping can be found at Scheme from Scratch [6] or even on Wikipedia [7].


OpenJDK8 [8] is compiled and built using JDK7, similarly OpenJDK9 [9] is compiled and built using JDK8. In theory OpenJDK8 can be compiled using the images created from OpenJDK8, similarly for OpenJDK9 using OpenJDK9. Using a process called bootcycle images – a JDK image of OpenJDK is created and then using the same image, OpenJDK is compiled again, which can be accomplished using a make command option:
$ make bootcycle-images       # Build images twice, second time with newly built JDK

make offers a number of options under OpenJDK8 and OpenJDK9, you can build individual components or modules by naming them, i.e.

$ make [component-name] | [module-name]
or even run multiple build processes in parallel, i.e.
$ make JOBS=<n>                 # Run <n> parallel make jobs
Finally install the built artefact using the install option, i.e.
$ make install


Some myths busted
OpenJDK or Hotspot to be more specific isn’t completely written in C/C++, a good part of the code-base is good ‘ole Java (see the composition figure above). So you don’t have to be a hard-core developer to contribute to OpenJDK. Even the underlying C/C++ code code-base isn’t scary or daunting to look at. For example here is an extract of a code snippet from vm/memory/universe.cpp in the HotSpot repo –
.
.
.
Universe::initialize_heap()

if (UseParallelGC) {
#ifndef SERIALGC
Universe::_collectedHeap = new ParallelScavengeHeap();
#else // SERIALGC
fatal("UseParallelGC not supported in this VM.");
#endif // SERIALGC

} else if (UseG1GC) {
#ifndef SERIALGC
G1CollectorPolicy* g1p = new G1CollectorPolicy();
G1CollectedHeap* g1h = new G1CollectedHeap(g1p);
Universe::_collectedHeap = g1h;
#else // SERIALGC
fatal("UseG1GC not supported in java kernel vm.");
#endif // SERIALGC

} else {
GenCollectorPolicy* gc_policy;

if (UseSerialGC) {
gc_policy = new MarkSweepPolicy();
} else if (UseConcMarkSweepGC) {
#ifndef SERIALGC
if (UseAdaptiveSizePolicy) {
gc_policy = new ASConcurrentMarkSweepPolicy();
} else {
gc_policy = new ConcurrentMarkSweepPolicy();
}
#else // SERIALGC
fatal("UseConcMarkSweepGC not supported in this VM.");
#endif // SERIALGC
} else { // default old generation
gc_policy = new MarkSweepPolicy();
}

Universe::_collectedHeap = new GenCollectedHeap(gc_policy);
}
. . .
(please note that the above code snippet might have changed since published here)
The things that appears clear from the above code-block are, we are looking at how pre-compiler notations are used to create Hotspot code that supports a certain type of GC i.e. Serial GC or Parallel GC. Also the type of GC policy is selected in the above code-block when one or more GC switches are toggled i.e. UseAdaptiveSizePolicy when enabled selects the Asynchronous Concurrent Mark and Sweep policy. In case of either Use Serial GC or Use Concurrent Mark Sweep GC are not selected, then the GC policy selected is Mark and Sweep policy. All of this and more is pretty clearly readable and verbose, and not just nicely formatted code that reads like English.


Further commentary can be found in the section called Deep dive Hotspot stuff in the Adopt OpenJDK Intermediate & Advance experiences [11] document.


Steps to build your own JDK or JRE
Earlier we mentioned about JDK and JRE images – these are no longer only available to the big players in the Java world, you and I can build such images very easily. The steps for the process have been simplified, and for a quick start see the Adopt OpenJDK Getting Started Kit [12] and Adopt OpenJDK Intermediate & Advance experiences [11] documents. For detailed version of the same steps, please see the Adopt OpenJDK home page [13]. Basically building a JDK image from the OpenJDK code-base boils down to the below commands:


(setup steps have been made brief and some commands omitted, see links above for exact steps)
 $ hg clone http://hg.openjdk.java.net/jdk8/jdk8 jdk8  (a)...OpenJDK8
or
$ hg clone http://hg.openjdk.java.net/jdk9/jdk9 jdk9  (a)...OpenJDK9
$ ./get_source.sh                                     (b)
$ bash configure                                      (c)
$ make clean images                                   (d)
(setup steps have been made brief and some commands omitted, see links above for exact steps)


To explain what is happening at each of the steps above:
(a) We clone the openjdk mercurial repo just like we would using git clone ….
(b) Once we have step (a) completed, we change into the folder created, and run the get_source.sh command, which is equivalent to a git fetch or a git pull, since the step (a) only brings down base files and not all of the files and folders.
(c) Here we run a script that checks for and creates the configuration needed to do the compile and build process
(d) Once step (c) is success we perform a complete compile, build and create JDK and JRE images from the built artefacts


As you can see these are dead-easy steps to follow to build an artefact or JDK/JRE images [step (a) needs to be run only once].


Benefits
– contribute to the evolution and improvement of the Java the language & platform
– learn about the internals of the language and platform
– learn about the OS platform and other technologies whilst doing the above
– get involved in F/OSS projects
– stay on top the latest changes in the Java / JVM sphere
– knowledge and experience that helps professionally but also these are not readily available from other sources (i.e. books, training, work-experience, university courses, etcetera).
– advancement in career
– personal development (soft skills and networking)


Contribute
Join the Adopt OpenJDK [13] and Betterrev [15] projects and contribute by giving us feedback about everything Java including these projects. Join the Adoption Discuss mailing list [14] and other OpenJDK related mailing lists to start with, these will keep you updated with latest progress and changes to OpenJDK. Fork any of the projects you see and submit changes via pull-requests.


Thanks and support

Adopt OpenJDK [13] and umbrella projects have been supported and progressed with help of JCP [21], the Openjdk team [22], JUGs like London Java Community [16], SouJava [17] and other JUGs in Brazil, a number of JUGs in Europe i.e. BGJUG (Bulgarian JUG) [18], BeJUG (Belgium JUG) [19], Macedonian JUG [20], and a number of other small JUGs. We hope in the coming time more JUGs and individuals would get involved. If you or your JUG wish to participate please get in touch.

—-

Credits
Special thanks to +Martijn Verburg (incepted Adopt OpenJDK),+Richard Warburton, +Oleg Shelajev, +Mite Mitreski, +Kaushik Chaubal and +Julius G for helping improve the content and quality of this post, and sharing their OpenJDK experience with us.

—-

How to get started ?
Join the Adoption Discuss mailing list [14], go to the Adopt OpenJDK home page [13] to get started, followed by referring to the Adopt OpenJDK Getting Started Kit [12] and Adopt OpenJDK Intermediate & Advance experiences [11] documents.


Please share your comments here or tweet at @theNeomatrix369.

Resources
[17] SouJava

This post is part of the Java Advent Calendar and is licensed under the Creative Commons 3.0 Attribution license. If you like it, please spread the word by sharing, tweeting, FB, G+ and so on!

Post #fosdem, #jfokus – lots more #java, #jsr & #openjdk news from all over!

In the last couple of weeks since FOSDEM 2013, Jfokus 2013 and, events and hackdays organised by LJC JUG members, we have had a lots of exciting news and resources to share with you. The source of the information have been mailing lists / forums, meetup events, twitter and other sources.

Plenty were spoken about #java, #jsr and #openjdk, the topics covered by the #adoptajar and #adoptopenjdk programs.

FOSDEM 2013

Speaker interviews:


Jfokus 2013

#Jfokus coverage of #java, a snapshot by Kevin Farnham:


@steveonjava – Nighthacking!

Watch all the recordings of Steve’s Nighthacking from FOSDEM 2013 through to Jfokus 2013!


LJC events & hackdays

Garbage collection – The useful parts


WebSocket & JSON Hack Day (covering implementation for JSR 356 & JSR 353)


Bring your Performance Problems Panel


@adoptajsr news feed

– Plenty of updates on polls, JSRs, presentations, github projects, etc… were discussed on twitter.
– WebSocket & JSON Hack Day (covering implementation for JSR 356 & JSR 353) – see above!
Suggestion to extend / improve the Java API – Thanks Hildeberto Mendonça for coming forward to contribute!
– Modernize Connector/MDB — Vote and comment – Thanks Richard Kolb for support such initiatives!
CDI 1.1 applications you can work with – Thanks Luigi for the contribution!


@adoptopenjdk news feed

– Updates on latest changes and developments in the OpenJDK world that were discussed amongs members on twitter.
– Potential plans to deprecate SPARC V8 support in HotSpot!
– StringBuffer to StringBuilder again – discussions rekindled!


Upcoming events and meetings

Adopt-a-JSR online meeting – February 27
Further hackdays, discussion panels and events to be organised by LJC JUG members.
26-27 March 2013, Devoxx UK

—-

Read about the Adopt OpenJDK program at the the Adopt OpenJDK java.net project website.
Join the Adopt OpenJDK mailing list at the google group. Find out how to join a Google group or send an email to adopt-openjdk@googlegroups.com to subscribe to the mailing list.

Read about the Adopt-a-JSR program at the java.net project website.
Join the Adopt-a-JSR mailing list at the java.net mailing list. Send an email to members@adoptajsr.java.net to subscribe to the mailing list.

The OpenJDK and JSR topics get good coverage at FOSDEM 2013! JUG members participating!

Its FOSDEM (Free and Open source Software Developers’ European Meeting) time again, and this year we have very good coverage on the OpenJDK and JSR topics at FOSDEM 2013. A number of speakers and events are taking place throughout the two days covering various topics on Java.

Adopt-a-JSR and JSRs
The speakers and events for these topics will speak on the present state and the future of Java, technical topics like InvokeDynamics, Zero, and the Shark compiler. The new JSR for Hotspot/JVM that will affect the Android world i.e. Dalvik users! Below are a list of speakers and events covered under this topic.

Speakers

Events

Adopt OpenJDK / OpenJDK
The OpenJDK topic has got massive coverage with 17 speakers, speaking and holding events covering various topics. In summary the topics covered will be:

– Past and future of OpenJDK, new releases
– Q & A session on OpenJDK
– The OpenJDK journey and what has been learnt so far
– Porting OpenJDK to PowerPC/AIX, AArch64
– Running Nashorn and JavaJFX
– OpenJDK7u progress
– Highlight on OpenJDK Lambda
– Using Shark again

Below are a list of speakers and events covered under this topic.
Speakers

Events

Java gets its own space in the Free Java (Dev Room).

Members of the LJC JUG, CEJUG, Brussels JUG and other JUGs worldwide will be present at this event!

Follow the event on Twitter by following the below handles:
@fosdem
@adoptopenjdk
@adoptajsr

FOSDEM website: https://fosdem.org/2013/

Read about the Adopt OpenJDK program at the the Adopt OpenJDK java.net project website.
Join the Adopt OpenJDK mailing list at the google group or send an email to adopt-openjdk@googlegroups.com to subscribe to the mailing list. Find out how to join a Google group.

Read about the Adopt-a-JSR program at the java.net project website.
Join the Adopt-a-JSR mailing list at the java.net mailing list. Send an email to members@adoptajsr.java.net to subscribe to the mailing list.

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