What’s hot? Tech Trends That Made a Real Difference in 2017

At Java One 2017 I had the pleasure to be interviewed in a podcast with industry legends such as Chris Richardson, Lucas Jellema and others:

“In order to get a sense of what’s happening on the street, we gathered a group of highly respected software developers, recognized leaders in the community, crammed them into a tiny hotel room in San Francisco (they were in town to present sessions at JavaOne and Oracle OpenWorld), tossed in a couple of microphones, and asked them to talk about the technologies that actually had an impact on their work over the past year. The resulting conversation is lively, wide-ranging, often funny, and insightful from start to finish. Listen for yourself.”

For those who care, this was last year’s interview about “The Role of the Cloud Architect”.

Devoxx 2017 Presentation: Serverless Architectures (AWS Lambda + Fn Project)

Devoxx 2017 in Casablanca has come to an end. I enjoyed this fabulous conference a lot. Highlights were the the Serverless presentations, the istio presentation by Google, the Spring people live coding, and the Kotlin session that showed that my own Kotlin in the cloud HelloWorld was not so bad after all. Tech content is one important part, but also the great atmosphere and focused but relaxed environment with superb lunches were something to write home about.

And here is my presentation:

Video recording doesn’t seem to be uploaded on Youtube yet. Fun fact: We almost bought a flying carpet after Devoxx in Casablanca!

With the same slideset I gave my Serverless presentation at DOAG 2017 conference. Thanks again folks for the marvellous feedback 🙂

With Kotlin and Spring Boot to the Clouds

0. Overview

This posting is based on a quick customer demo that I did the other week. It demonstrates running Kotlin code in different public clouds. To be more precise: We use Kotlin together with Spring Boot to create a somehow minimalistic REST-like application that is running on multiple, load balanced instances on AWS Beanstalk or Oracle ACCS.

1. Kotlin

Kotlin is one of the upcoming, trendy JVM-based languages. It’s syntax is close to Java, but just sometimes more convenient. The language is backed by two industry giants: Pivotal announced support forSpring and Google officially supports Android development with Kotlin.

The Kotlin language follows the Java coding conventions, but makes the semicolon mostly optional (great!) and adds null-pointer safety (you never had problem with this in Java, did you?) and string interpolation on top of that. Although Kotlin packages are same as in Java in reverse order, in Kotlin package names don’t have to match to folder structure (great!). Interesting enough, most Kotlin control structures are expressions.

2. Spring Boot

We will use Kotlin together with Spring Boot in this posting.

Project Creation

For the purpose of this demo we will create the smallest possible application that is still helpful to learn about the synergy of Kotlin, Spring Boot and cloud. To get started, we create a maven project  for Spring Boot with the spring.io initializer.

The project will contain an empty Spring Boot application and the maven pom file amongst others.

Add a Controller

To get some meaningful output we add another Kotlin class: a controller with three functions. Did you know, the “fun” in Kotlin is for function?

  1. the hello(World) function that simply echoes a name.
  2. a func that shows how to access java.util.Date from Java and returns the time.
  3. a info func that show a bit of load balancing magic when deployed on ACCS.

Build the Project

We can build the project with mvn package from the command-line (or from the IDE, as shown in the web cast).

IDE Support for Kotlin

Being developed by Jetbrains, Intellij offers great support for Kotlin. In this webcast I simply use Netbeans.


3 Kotlin in the Clouds

This little demo is more real life than you might think. I will show you to run Kotlin in two different clouds. These days I see multiple clouds at my customers usually. Simply choose the one you like most.

3.a ACCS

ACCS is a Oracle Public Cloud PaaS service that provides several language runtimes. ACCS is based on Docker containers, but don’t worry, you won’t see any of them. With ACCS you can easily deploy Java, Java EE, as well as Python, Ruby, NodeJS and even Go code. Also it supports spinning up multiple instances with load balancing.

Deploying a .jar file on ACCS is as straight forward as it gets:

  1. zip it.
  2. upload it.
  3. run it.

However, there is one more thing: to successfully run the .jar file we need to add a manifest.json file that contains the exact command how the jar file will be started in the Java container. It should be all obvious watching the webcast. Check my other posting to learn about ACCS and Java EE.

3.b Beanstalk

The AWS Beanstalk deployment isn’t more complicated than the ACCS one. Actually even the manifest.json file can be omitted. Beanstalk implicitly understands how to run a .jar file (which of course is easy in most cases: java -jar demo.jar). So all you need to do is upload to Beanstalk. However with Beanstalk we have to make sure to include a SERVER_PORT variable and set its value to 5000. This is required since Beanstalk is internally listening to port 5000 but Spring Boot uses 8080.

5. Web cast

I created a web cast for you with all the details.

6. Ressources

Some additional resources that you might find useful:

  1. Kotlin language
  2. Try Kotlin online
  3. Spring Initalizer
  4. Get started with ACCS
  5. Access the demo code from github. TO DO.
  6. AWS Beanstalk



Application Container Cloud (ACCS) supports Java EE

This is my personal entry for the ODC appreciation day that was initiated once more by Tim Hall.


Oracle’s Application Container Cloud Service (ACCS) is a cloud native, container based runtime for applications and microservices implemented with Java, Node.js, Ruby, Python and PHP. It’s simplicity makes it most attractive. All you need to do is bundle and upload your code, and add a .json file to let ACCS know how to start your application.

Since a couple of days ACCS is now supporting Java EE as well – this is great news! Note, that there is still Java Cloud Service JCS, which gives you a fully fledged WebLogic domain. However, JCS is more complex to set up and to deploy to, so ACCS is a good option for those that only want to deploy and run a Java EE module.

ACCS with Java EE

The provisioning, as shown in the following screenshot, is PaaS-worthy, easy enough as with any other ACCS deployment type.

ACCS: Application Container Cloud Service with Java EE


ACCS with Java EE, Some Details

Here are some more facts as they are currently known:

  • You can simply upload a .war file. The .json manifest that is required to tell ACCS how to start a Java application is not mandatory for Java EE since the module is running in WebLogic.
  • The current versions used in ACCS when deploying a Java EE module are: WebLogic (which supports Java EE 7), running on Java 8.
  • ACCS with Java EE currently does not support clustering.
  • ACCS does not let you access the WebLogic admin console. This is fine. It’s PaaS!
  • ACCS with Java EE can make use of Java Flight Recorder. In continuous mode, all profiling and event data is captured. If Java Flight Recorder is not in continuous more, then 60 seconds of data is captured. You can download the files and use Java Mission Control to analyze the recordings.
  • The URL syntax to invoke a deployed web module is as follows:


  • Typically the URL to call a deployed application is shown in the ACCS service console. Note, that the DocRoot -even if required to call the deployment – is not shown.
  • A Java EE deployment is running across 2 instances as default which requires a load balancer to be provisioned by ACCS. Currently OTD is used.
  • If you feel brave enough, just give it a go and deploy the sample app.
  • If you are lost working with ACCS by yourself, then follow this tutorial, explaining how to deploy a Java EE module to ACCS. The instruction mentioned in the tutorial worked OOTB for me.

Possible Improvements

As you know, I usually write about features and showstoppers. A few minor things that should be improved in my opinion:

  • A few minor details are not visible in the console. E.g. the used Java version is not fully displayed.
  • Not sure if it is documented somewhere, but I would love to read more precisely about current restrictions for Java EE in ACCS. Actually I dropped the hint for some colleagues at Oracle to blog about it.

Is it Java EE or EE4J now?

You may have heard that Java EE went to the Eclipse foundation. The new name will be EE4J. Do you have to change all your slide decks and articles? Actually no. For some more details have a look at this article.


Many thanks to the team of Abhishek and Sriram for helping to clarify some questions and providing quick and precise feedback!

Purge / Empty / Drain a Kafka Topic in Oracle Event Hub Service (or any other Kafka broker)

I did not find this solution myself, but I am also not sure where I discovered it. Just a note to myself.

Actually it is becomes useful once you enabled client access to your Oracle Event Hub Cloud Service, since the web based console itself does not implement every functionality that is provided by Kafka.

# PURGE topic
# we drain the topic by expiring the messages

./kafka-topics --zookeeper ZKADR --alter --topic topic_name --config retention.ms=1000
./kafka-topics --zookeeper ZKADR --alter --topic topic_name --delete-config retention.ms

On another thought: what if the Event Hub Console implemented draining a topic in the web console? And maybe it could also display the number of messages stored in topic.