Friday Dec 13, 2013

Interview: Simon Ritter, Oracle Java Evangelist

In this interview, Simon Ritter, Head of Java Evangelism at Oracle, discusses "the Lambda Mindshift," the Internet of Things and his Raspberry Pi "carputer." 

You can always find more Java videos: interviews, demos, and hacking at the YouTube/Java channel. 

Tuesday Oct 01, 2013

At the Java Demogrounds: What’s Happening with Java SE?

Over at the Java SE demo booth, Oracle’s Aurelio Garcia-Ribeyro, Senior Group Product Manager, briefly discussed JDK 7 and  JDK 8.

“People may not realize that we’ve recently added new functionality to JDK 7,” he said. “So with JDK 7 u40, we added Mission Control and Flight Recorder to the JDK, something we're very proud of. Flight recorder is a feature that works a little like the flight recorder on a plane; you leave it on and it doesn’t really impact your production. It simply runs, and if you encounter an issue, you can go back and discover what triggered it after the fact. It’s quite useful in debugging horrible problems that occur only in production that you cannot really catch when you’re developing because you need it to be going for 15 days with a slow memory leak, but you don’t want to have to reproduce that because it’s costly and you don’t know when it happens. With flight recorder you just leave it on, set a trigger, and when something goes bad, it helps you figure out what triggered that event.”

I asked him about Java SE 8, which is scheduled for release in March of 2014.

“If you want to play with it, go to and download the developer preview. We’d like you to first try your existing projects, which should work just fine. Then after that, you should start playing with the new features like lambda and JSR 310, the Date and Time API. Lambda is the biggest change to the developer programming model. We are very excited about this.”

Tuesday Sep 24, 2013

Session Report: JSR 341: Expression Language 3.0

Ed Burns, Consulting Member of Technical Staff, and Kinman Chung, Principle Member of Technical Staff, both at Oracle, presented a session on Monday in which they described new features in JSR 341, Expression Language (EL) 3.0. They discussed the APIs for the use of EL in standalone environments and EL syntax for new operators, plus lambda expressions, and support for collection objects, all the while offering copious code illustrations.

Burns remarked that he was pleased that Java Champion and JavaOne Rock Star Adam Bien had referred to EL 3.0 as “the hidden gem of Java EE”. “I don’t know how hidden it is,” said Burns, “but I think it’s a gem.”

He discussed the origins of EL, which has a long and active history in the Java platform. EL began in 2004 as part of the Java Standard Tag Library (JSTL 1.0), moved to JSP 2.0 in 2006, and became an independent specification with JSR 341 in 2011. It is used in JSF, CDI, and Avatar. Now, 9 years after its inception, it is an independent specification that is heavily used in JSF.   

Burns observed that the presence of EL is the key differentiator between Java server and non-java server stacks. “Java server-based web frameworks are likely to use EL,” said Burns. “When you show someone who is not familiar with EL how easy it is to move things together from disparate parts of your application, it’s very compelling.”

The most important feature that EL 3 brings is lambda expressions – developers do not have to wait until Java SE 8 is released. It all runs on Java EE 7, which requires Java SE 7 -- which means that it is currently available. Burns gave a brief discussion of lambda expressions, which basically behave like an anonymous function -- lambdas in EL are EL expressions. They offer full access to the EL environment within the body of the EL lambda expression, something not available from Java SE lambdas. “You won’t be able to refer to other EL things from a plain old SE lambda expression,” said Burns.

The goal of EL 3 is to provide greater expressive power for applications and to use it outside of Java EE. Burns and Chung provided an overview of collection operations and explained EL’s support for stand-alone environments. EL 3 is easy to use outside of Java EE and provides standard data structures: ELContext; ELResolvers; and local variable and function repositories.

They explained that it enables direct EL operations and has: EL expression evaluation; Bean definition; and Function definition. They emphasized that other key parts of Java EE can also be used standalone, such as: Bean Validation; Persistence (JPA); and Contexts and Dependency Injection (CDI). They encouraged developers to consider the possibilities for cloud deployment in: Defining functions and variables and defining beans.

They spent the rest of the session illustrating their key points with a healthy dose of code.

Links and Downloads:
* JSR 341:
    Download spec and API javadocs

* Project home:
   Report spec bugs or RFE for

* RI:
   Maven artifacts available from Maven Central
   Download source and report RI bugs

* Integrated in Glassfish 4.0:

You can listen to this session in early October on

The Eleventh Annual Java Community Process Program Awards

by Timothy Beneke and Janice J. Heiss

In a festive room teeming with over 200 people, including many celebrated Java luminaries,
along with excellent food and drink, the 9th annual JCP Program Awards were handed out atop the majestic Hilton Hotel on Monday night. As the JCP states, “The Java Community Process (JCP) program celebrates success. Members of the community nominate worthy participants, Spec Leads, and Java Specification Requests (JSRs) in order to cheer on the hard work and creativity that produces ground-breaking results for the community and industry in the Java Standard Edition (SE), Java Enterprise Edition (EE), or Java Micro Edition (ME) platforms.”

The JCP added a new awards category this year for Adopt-a-JSR program participants, bringing the total to four: JCP Member/Participant of the Year, Outstanding Spec Lead, Most Significant JSR, and Outstanding Adopt-a-JSR Participant.

The room was full of good cheer, playful humor, a music band of Java developers, and enthusiastic appreciation of much that has been accomplished on behalf of Java technology in the previous year.

The nominees and winners in their respective categories were:

JCP Member/Participant of the Year

--Azul Systems, Gil Tene

--London Java Community (LJC), Ben Evans, Martijn Verburg, Richard Warburton, Graham Allan

--Mohamed Taman

The winner was Azul System’s Gil Tene. The JCP said, “Gil has worked diligently to provide clear advice on matters of Software Patents, IP and licensing that seeks to benefit both non-profits/individuals etc as well as organizations with vested commercial interests in Java. It's not easy delving into the depths of the legal aspects and the potential impacts of changes to the JCP, but with help from folks like Gil we're hopeful for a solid and fair outcome.”

Tene characterized his approach to the JCP as follows: “I represent Azul Systems on the JCP EC, but I try to apply an approach of ‘do the right thing first’ in my choices and positions. Coming from a small company that depends on Java and its ecosystem for its livelihood, I see my role as representing the interests of an entire sector of non-big-company commercial folks and of individual and professional developers out there, and providing some offset and balance to the normal mix of such boards.”

Outstanding Spec Lead

--Brian Goetz, Oracle

--Jitendra Kotamraju, Oracle

--Anatole Tresch, Credit Suisse

--Chris Vignola, IBM

The winner, Oracle’s Brian Goetz, was recognized, “For tirelessly working away at an incredibly complex JSR - JSR 335, Lambda Expressions for the Java Programming Language. From a community point of view, we've appreciated his willingness to listen and consider ideas from other technologists as well as spending time with groups of developers to understand the impact of Lambdas on Java.”

Goetz offered a statement in response to the award for his leadership in creating Lambda Expressions for the Java Language, which also won for most significant JSR. He said that lambdas, “represent a coordinated co-evolution of the Java SE platform, including the VM, language, and core libraries to provide developers with a powerful upgrade -- quite likely the largest ever -- to the Java SE programming model. We started this JSR in early 2010, but the topic of closures-in-Java had already been in play in the community for many years prior, and, of course, there was a broad diversity of opinions as to what direction, how far, and how fast to evolve the Java programming model. In the end, the most significant dimension of the challenge turned out to be: how do we integrate these new features in the language and libraries without them feeling grafted on after-the-fact. I think developers will find programming with this ‘new and improved Java’ to be a very pleasant experience -- I know I have.”

Most Significant JSR

--JSR 335, Lambda Expressions for the Java Programming Language

--JSR 344, JavaServer Faces (JSF) 2.2

--JSR 352, Batch Applications for the Java Platform

--JSR 354, Money and Currency API

--JSR 355, JCP Executive Committee Merge

The winner, as previously mentioned, was JSR 335, Lambda Expressions for the Java Programming Language, which the JCP praised as follows:

“This brings Java kicking and screaming into the modern programming language age and is seen as a catalyst for the second age of Java. It's underlying discoveries and improvements with regards to Type Inference has also resulted in a stronger JVM for all.”

Spec lead Brian Goetz, in picking up the award, remarked, “This is something we’ve been working on for three-and-a-half-years and it’s nice to be looking at it through the rear-view mirror.”

Outstanding Adopt-a-JSR Participant

--BeJUG, Johan Vos

--CeJUG, Helio Frota, Hildeberto Mendonça

--JUG Chennai, Rajmahendra (Raj) Hegde

--Morocco JUG and EGJUG, Mohamed Taman, Faissal Boutaounte

The winner was Morocco JUG and EGJUG, Mohamed Taman, and Faissal Boutaounte, who were praised, “For adopting JSR 339, JAX-RS 2.0 specification, along with many other JSRs. One JIRA issue filed by Morocco JUG on JSR 339 was classified as a ‘release-stopper’. A quick JIRA search using the ‘adoptajsr’ tag shows that most of the JIRA issues have been created by MoroccoJUG members. Several presentations and source code have been organized by these groups. Mohamed presented sessions about the upcoming technologies to widen the range of users in the future, especially Java EE 7 JSRs and spreading of community progress and contributions that make us encouraged to participate. Mohamed sent a clear message that Africa is here and is full of talented people who are willing to take it to the next level. Mohamed was responsible for translating an Arabic Adopt-s-JSR web page to allow more Arabs to participate.”

Taman said that, “Currently, I hold two positions, one as a Business Solutions Systems Architect and design supervisor and Java Team leader, at a big financial services company in Egypt, which affects all the country by building solutions affecting Egyptians every day, by providing more facilities for businesses and enhancing the economy… I am passionate about Java. I really love it and have fun coding, and love seeing it grow, day by day, as if it were my kid.”

The Annual Java Community Process Program Awards at  JavaOne is an event and party not to be missed!

The Java Community Process

Monday Sep 23, 2013

The JavaOne 2013 Technical Keynote

by Timothy Beneke

Mark Reinhold, Oracle’s Chief Architect, the Java Platform Group, took the stage to kick off Sunday’s technical keynote at the Moscone Center. He began by quoting “father of Java” James Gosling. For Java to thrive, it must maintain what Gosling called the “feel of Java”. In other words, it must retain the key values of readability, simplicity, and universality.

“If we keep those,” said Reinhold, “then Java will remain not just productive but fun. It is not enough to simply add popular features each year.”

Lambda Expressions – The Single Largest Upgrade Ever
He turned to lambda expressions, which he described as the single largest upgrade to the programming model ever -- larger even than generics. “This is the first time we have done a carefully coordinated co-evolution of the JVM, the language, and the libraries all together – and the results still feel like Java,” said Reinhold.

He then welcomed Oracle Java Language Architect, Brian Goetz, to share the stage and began by remarking that while most developers understand that lambda offers a simple way to express code as data, some are not sure how it helps Java. Goetz responded that lambda expressions would more than help Java. “It’s going to change the way we all program in Java every day,” he explained. “Programming well is about finding the right abstractions. We want the code we write to look like the problem statements it’s trying to solve, so we can look at it and immediately know it’s correct. Java has always given us good tools for abstracting over data types. I wanted to do better in abstracting over patterns of behavior – that’s where lambda comes in.”

He illustrated this with some simple code that was, strictly speaking, “good” code, but weighed down with boilerplate and did not read like the problem statement it was trying to solve. It could be improved by using an inner class tool, but that too generated a lot of boilerplate. Reinhardt pointed out that improving the code made it less pleasant to work with, as if the developer was being punished for doing the right thing. This often causes developers to give up and do it the “dumb and ugly way”.

Lambdas can replace inner classes with a lambda expression which is simply an anonymous method that captures a behavior without a lot of syntactic boilerplate. “Lambdas are a nicer syntax,” said Goetz. “But they are also something deeper. It’s not just a compiler generating inner classes for you – it uses the invokedynamic feature to get more compact and higher performance code. It will make a qualitative difference in the way we program.”

If the right way to write a program is unpleasant, then people are less likely to do it according to Goetz. They are more tolerant of doing it the wrong way. He gave an example of how lambda expressions address this with the collections API involving a new abstraction to the JDK called stream and showed how to represent a simple query through applying a filter and mapping transformation, followed by an aggregation, in a way that is fused into one path without creating any intermediate weapons.

Reinhold summarized the key points: “So lambda brings 3 weapons to Java – syntax, performance and abstraction.”

“Plus parallelism,” Goetz added. He explained that Java 7 has the fork/join framework for parallel decomposition that is powerful, flexible, and highly efficient – but not the easiest thing to use. Goetz showed how lambdas enable better parallelism without needing to write fork join code: by asking the collection for a parallel stream it uses fork/join under the hood.

Lambda also helps with normal sequential code by making code clearer, less noisy, and easier to read. “When you have code that is hard to read, that’s where bugs come from. You are trying to maintain some code, you look at the code and think you know what it does, but don’t actually know what it does, and boom! – you’ve introduced a bug.”

All in all, the message was clear: Lambda expressions make Java code easier to read and easier to write.

Working with Lambda and the Collections Framework
For lambdas to be successful, they must work with the Java Collections Framework, which is now 15 years old. So an evolution of the interface was in order. Goetz’s team had to grow an interface over time without breaking implementations of the interface. They added a concept that allows developers to compatibly add a method to an interface, as long as a default implementation is provided.

Reinhold remarked that he has now written a couple of thousand lines of code with lambda features and really enjoyed it. “I can be more productive, and the end result still feels like Java,” he said.

To get started learning lambda expressions, Java developers can go to the OpenJDK Project Lambda page and download the developer preview builds there.

Reinhold reminded attendees that there is a great deal more in Java SE 8 besides lambda expressions. Developer preview builds can be downloaded at “Now is a great time to download JDK 8 and take it for a spin. Every planned feature is in there. It’s reasonably stable and it passes almost all of the tests. If you have any feedback, please send it in!” said Reinhold. 

Playing Chess
In the rest of the technical keynote, Oracle’s John Ceccarelli, head of engineering for Oracle’s NetBeans team and Oracle’s JavaFX architect Jasper Potts, arrived on stage to demonstrate a Duke pad running real Java via a chess program that was connected to a server. The iPad operated through an HTML5 client talking to a Java EE 7 back end with an EE server in charge of  messaging, communication, game state, and so on, with clients hook into it – all built with NetBeans. Jasper Potts further showed off the chess demo with an HTML5 client using a front end to a chess server that was managing the chess games. Then a robot, powered by Java ME 8, took over the game.

Oracle Software Engineer, Santiago Pericas Geertsen, who built the chess server, also described how it was built with 5 distinct functional modules.

In sum, attendees witnessed a server running Java EE 7 hooked up with a variety of clients, some written in HTML5, one written in JavaFX on a Duke pad, one using JavaFX 3D on a powerful laptop, plus a Java ME 8-powered robot contributing to the ongoing chess game. In the process, the powers of the Raspberry Pi were demonstrated.

Developers were encouraged to jump in the water, go for a swim, and have fun with NetBeans and Java embedded.

Java SE 9 and Beyond
Wrapping it up, Reinhold peered a bit into the future and suggested some possible directions for Java, some of which are already in development:

One is Java on GPUs, graphic processing units. As GPUs are being used more and more widely to process big data he suggested that it would be good to make Java work directly with the GPU rather than having to call out to some primitive interface. An OpenJDK called Sumatra has people working on this.

Reinhold spoke of the need for reification. Java’s generics, added in 2004, are based on the notion of erasure for good technical reasons as a sound way to create a type system that supports migration compatibility. But this creates programming problems in which the erasure approach severely limits what can be expressed. Reinhold suggested that introducing some reification and eliminating the “annoying dichotomy between primitive and reference types” would be of value.

He mentioned JNI 2.0 and said, “It just shouldn’t be so hard to integrate Java with native code after all these years.”

He called for memory efficient data structures: “As we get into big data – all this boxing and pointer chasing makes it hard to do big data well. We could have less boxing and pointer chasing and load a lot more data into memory.”

Finally, he talked about the notion of a truly modular platform. “The compact profile in Java 8 is a start but it is not flexible enough. We need to continue to unify the Java SE and Java ME platforms.”


OpenJDK Project Lambda

Watch Keynote and Session Highlights on Demand

Friday Sep 13, 2013

An Interview with Venkat Subramaniam before JavaOne

JavaOne Rock Star and Java Champion, Venkat Subramaniam, sees a lot to be excited about with regard to Java.[Read More]

Josh Juneau – Learning More at JavaOne

Jython expert Josh Juneau on Java development today.[Read More]

Thursday Aug 15, 2013

Trying Out Lambda Expressions in the Eclipse IDE

A new article, now up on otn/java, by Deepak Vohra, titled “Trying Out Lambda Expressions in the Eclipse IDE,” demonstrates how to take advantage of lambda expressions in Java SE 8 using the Eclipse IDE and virtual extension methods.

Vohra begins with the basics:
“Lambda expressions, also called closures, are a short-form replacement for anonymous classes. Lambda expressions simplify the use of interfaces that declare a single abstract method, which are also called functional interfaces. In Java SE 7, a single method interface can be implemented with one of the following options.
* Create a class that implements the interface.
* Create an anonymous class.”

Vohra explains that while lambda expressions can be used to implement a functional interface without creating a class or an anonymous class, they can be used only with interfaces that declare a single method.

Benefits of lambda expressions include:
* Concise syntax
* Method references and constructor references
* Reduced runtime overhead compared to anonymous classes

Vohra gets under the hood to explain the basics of lambda syntax, along with the nature of functional interfaces and target types, offering copious examples. All in all, the article offers a first-rate primer on how to make use of lambda expressions and virtual extension methods using the Eclipse IDE.

Check out the story here.

Sunday Sep 30, 2012

The Java Specialist: An Interview with Java Champion Heinz Kabutz

Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean.

Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science.

He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them.

Q: Tell us about your JavaOne plans.

A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies.

Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.)

Q: What sessions are you attending that we should know about?

A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.

In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.

Q: Give us an update on the Java Specialists’ Newsletter.

A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.

As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.

After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.

Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.

Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.

Here is a little memory puzzle for your readers:

public class JavaMemoryPuzzle {
  private final int dataSize =
      (int) (Runtime.getRuntime().maxMemory() * 0.6);

  public void f() {
      byte[] data = new byte[dataSize];
    byte[] data2 = new byte[dataSize];

  public static void main(String[] args) {
    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();

When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.

So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError:

public class JavaMemoryPuzzlePolite {
  private final int dataSize =
      (int) (Runtime.getRuntime().maxMemory() * 0.6);

  public void f() {
      byte[] data = new byte[dataSize];

    for(int i=0; i<10; i++) {
      System.out.println("Please be so kind and release memory");
    byte[] data2 = new byte[dataSize];

  public static void main(String[] args) {
    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();
    System.out.println("No OutOfMemoryError");

Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself.

Q: What do you think Java developers should know that they currently do not know?

A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.

Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?”

Q: What are you looking forward to in Java 8?

A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.

I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.

Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.

What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

Originally published on


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