Screencast: pushing a Java EE app to Oracle Cloud

Here is a screen cast to show case how you can easily push a Java EE application to Oracle Application Container Cloud from your command line



  • start with a Java EE 7 Maven archetype — mvn archetype:generate -Dfilter=com.airhacks:javaee7-essentials-archetype
  • modify the code — add a simple JAX-RS resource and build the project with mvn clean install
  • add (tiny bit of) metadata (deployment.json)


Further reading


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Session @ Oracle Code San Francisco 2017

Here are the details for my talk @ Oracle Code (a track at JavaOne 2017) – Streaming Solutions for Real time problems (Stream Processing solutions using Apache Kafka, Kafka Streams and Redis)

Code (Github) –




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New release: REST assured with JAX-RS




REST assured with JAX-RS is now updated for JAX-RS 2.1 – a new chapter has been added to cover its new features. You can read it on Gitbook or grab it via Leanpub


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Handling custom objects with JAX-RS SSE API

Information sent using the JAX-RS 2.1 SSE support (in Java EE 8) does not only have to be of String type – it supports Java primitives (Integer , Long etc.), JSON-B & JAX-B annotated types as well as custom objects whose encoding process (Java object to on-wire format) is defined using a MessageBodyWriter implementation

Here is simple example you can try out – no need to setup anything except Docker !

Meanwhile – here is the code snippet

To summarize

  • Multiple ​​OutboundSseEvents have been created – each differing in the data/media type (text, json, xml etc.)
  • the default SSE media type is TEXT_PLAIN, hence does not need to be explicitly specified when dealing with String data type
  • ​​​​​Employee class is a JSON-B annotated class
  • Customer is a JAX-B annotated class
  • Student has a custom MesaageBodyWriter implementation

For more details, just refer to the project

Further reading


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CompletionStage support in server-side JAX-RS

JAX-RS 2.1 (part of Java EE 8) now supports returning a CompletionStage to mark the request as eligible for asynchronous processing. This is in addition to the AsyncResponse API which has been available since JAX-RS 2.0 (Java EE 7)

Even the Client API has added support for reactive-style programming by providing support for CompletionStage API, but this blog will focus on the server-side support

The advantage this approach has over the AsyncResponse based API is that it is richer and allows you to create asynchronous pipelines. Let’s look at an example – available on Github. It is simple and slightly contrived, but hopefully it should help get the point across 🙂

  • It starts with a HTTP GET to /booking/cabs/<user> which invokes the getCab method
    • the method returns a CompletionStage and returns immediately
    • the thread which served the request is now freed up
  • and then its about creating the asynchronous pipeline
    • we orchestrate the tasks for user validation and driver search using thenComposeAsync – this gives a CompletableFuture i.e. the searchDriverTask
    • we then supply a Function which takes the driver (returned by the above step) and invokes the notifyUser method – this is the CompletionStage which we actually return i.e. notifyUserTask – this is obviously executed later on, all we did was compose the sequence
  • once the process is completed (delays are introduced using Thread.sleep() ), the response is sent back to the user – internally, our CompletableFuture completes

To run using Docker


Further reading

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JAX-RS 2.1 SSE Client API example using Glassfish 5 on Docker

Along with the Server API for SSE, JAX-RS 2.1 (part of Java EE 8) also has an equivalent client side API

Here is a quick peek – you can grab the project from Github

To summarize

  • we use a @Singleton EJB with @Startup
  • during initialization
    • create a single action (one time) Timer  i.e. @PostConstruct
    • and instantiate the SSEEventSource – its a public SSE source
  • when the timer expires, the @Timeout annotated method gets triggered
    • opens the SSE connection
    • prints them out – this action is registered as a callback (written as a Java 8 lamda in this case)
  • Execution thread pool(s) – notice this in the logs
    • the timer itself is triggered in the EJB thread pool
    • SSE event callbacks are executed in the ManagedExecutorService thread pool (thanks to Java EE Concurrency Utilities)


To run using Docker


Further reading


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Try out JSON-B 1.0, JPA 2.2 using Java EE 8 on Glassfish 5 & Docker

Glassfish 5 Build 11 is now available – with support for many of the Java EE 8 specifications e.g. JAX-RS 2.1, JPA 2.2, JSON-B 1.0 etc. For more details check out the Aquarium space. This blog covers


It’s a simple one – available on Github

  • Has a REST endpoint (also a @Stateless bean)
  • Interacts with an embedded (Derby) DB using JPA – we use the jdbc/__TimerPool present in Glassfish to make things easier
  • Test data is bootstrapped using standard JPA features in persistence.xml (drop + create DB along with a SQL source)

JSON-B 1.0 in action

Primarily makes use of the JSON-B annotations to customize the behavior

  • @JsonbProperty to modify the name of the JSON attribute i.e. its different as compared to the POJO field/variable name
  • @JsonbPropertyOrder to specify the lexicographical reverse (Z to A) order for JSON attributes

For more, check out Yasson which is the reference implementation

JPA 2.2 in action

The sample application uses the stream result feature added to Query and TypedQuery interfaces by which it’s possible to use JDK 8 Streams API to navigate the result set of a JPA (JPQL, native etc.) query. For other additions in JPA 2.2, please check this

Run on Docker and test…

Check the README


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CDI (2.0) Async Events

Glassfish 5 builds for Java EE 8 are rolling along… here is another Docker based example on Github. This time it’s asynchronous events in CDI 2.0 (JSR 365)


Just follow the README… just a bunch of docker commands to get started..!

What’s going on

Here is a quick summary

  • A Java EE scheduler triggers asynchronous CDI events (fireAsync())
    • These CDI events are qualified (using a custom Qualifier)
    • It also uses a custom java.util.concurrent.Executor (based on the Java EE Concurrency Utility ManagedExecutorService) – thanks to the NotificationOptions supported by the CDI API
  • Two (async) CDI observers (@ObservesAsync) – a JAX-RS SSE broadcaster and a Websocket endpoint
  • SSE & Websocket endpoints cater to their respective clients – details on how to connect in the README

Notice the asynchronous events running in Managed Executor service thread


You can choose to let things run in the default (container) chosen thread


Further reading




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Java EE + Debezium

I just published a post – Debezium test drive. It uses Kafka and Java EE… check it out if this interests you


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Glassfish 5: JAX-RS SSE quickstart

Latest Glassfish 5 build 08 was announced today which includes JAX-RS 2.1 (JSR 370) integration. I am fond of Server Sent Events (SSE), so let’s take it for a test ride – here is a Docker based quick start on Github



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