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• Sang Shin is back!

  - by arungupta

  Sang Shin is back at Oracle. He is well known for his wide range of Java tutorials at javapassion.com. As a former Sun evangelist, he helped GlassFish and Java EE adoption and continued to do even after his days at Sun. In his current role, he will help evangelize and drive adoption of the Java EE platform, GlassFish, and WebLogic server. You will see him online, speaking at conferences, blogging, and at our different social media channels. Say hello to him whenever you meet him. Here is what Sang had to say about his comeback: I AM BACK to where it all started. It sure felt like coming back home and it's good to see the first hand the spirit of innovation still is alive and well here in Oracle especially on Java front. Looking forward to be engaged with everyone in Java EE community with Passion again! Looking forward to working with Sang! You can ping him at @javapassion.

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• Java EE 6 and Maven 3 using CLI

  - by arungupta

  NetBeans and Eclipse provide tools, templates, wizards and code generators for building a Java EE 6 application. They both also allow a Java EE 6 Maven project to be created. In his recent screencast, Adam Bien explained how a Java EE 6 project can be easily created at command-line using Maven 3. The screencast walks through the process of creating the project using command-line. The created project has no dependency on NetBeans and GlassFish but can still be opened in NetBeans and deployed on GlassFish. A complete list of Adam's screencasts are available here. Tons of similar videos are also available on GlassFishVideos channel.

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• Java Embedded @ JavaOne Call for Papers

  - by arungupta

  Do you care about Internet of Things ? Interested in sharing your experience at javaOne about how you are using Java Embedded Technology to realize this vision ? At Java Embedded @ JavaOne, C-level executives, architects, business leaders, and decision makers from around the globe will come together to learn how Java Embedded technologies and solutions offer compelling value and a clear path forward to business efficiency and agility. The conference will feature dedicated business-focused content from Oracle discussing how Java Embedded delivers a secure, optimized environment ideal for multiple network-based devices, as well as meaningful industry-focused sessions from peers who are already successfully utilizing Java Embedded. Submit your papers for Business Track or Technical Content related to Embedded Java to be presented at JavaOne here. Speakers for accepted sessions will receive a complimentary pass to the event for which their session is submitted. Note, the CFP for the main JavaOne conference is over, speakers notified, and content catalog published. This is CFP only for Java Embedded @ JavaOne. Some key dates are: Jul 8th: Call for Papers closes Week of Jul 29th: Notifications sent Conference Dates: Oct 3, 4, 2012 And the main conference website is oracle.com/javaone/embedded.

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• Transactional Interceptors in Java EE 7 - Request for feedback

  - by arungupta

  Linda described how EJB's container-managed transactions can be applied to the Java EE 7 platform as a whole using a solution based on CDI interceptors. This can then be used by other Java EE components as well, such as Managed Beans. The plan is to add an annotation and standardized values in the javax.transaction package. For example: @Inherited @InterceptorBinding @Target({TYPE, METHOD}) @Retention(RUNTIME) public @interface Transactional { TxType value() default TxType.REQUIRED } And then this can be specified on a class or a method of a class as: public class ShoppingCart { ... @Transactional public void checkOut() {...} ... } This interceptor will be defined as part of the update to Java Transactions API spec at jta-spec.java.net. The Java EE 7 Expert Group needs your help and looking for feedback on the exact semantics. The complete discussion can be read here. Please post your feedback to [email protected] and we'll also consider comments posted to this entry.

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• Reminder: JavaOne Call For Papers Closing April 9th, 11:59pm

  - by arungupta

  JavaOne 2012 Call For Papers is closing on April 9th. Make sure to get your submissions in time and make the reviewers job exciting. Submit now! Read tips for paper submission here and an insight into the review process and more tips here. The conference will be held in San Francisco from September 30th to October 4th, 2012. And between now and this JavaOne in San Francisco, the conference is also going to Japan, Russia, and India.

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• GlassFish Community Event and Thirsty Bear Party - Reminder

  - by arungupta

  JavaOne is almost here! Here are some key activities that you don't want to miss out related to GlassFish: GlassFish Community Event - Sep 30, 11am - 1pm GlassFish and Friends Party - Sep 30, 8pm - 11pm Meet the Java EE 7 Specification Leads BoF - Oct 2, 5:30pm GlassFish Community BoF - Oct 2, 6:30pm Complete list of Java EE and GlassFish technical sessions, BOFs, and other presence is described at glassfish.org/javaone2012. See ya there!

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• Tab Sweep: Dynamic JSF Forms, GlassFish on VPS, Upgrading to 3.1.2, Automated Deployment Script, ...

  - by arungupta

  Recent Tips and News on Java, Java EE 6, GlassFish & more : • Dynamic forms, JSF world was long waiting for (Oleg Varaksin) • Creating a Deployment Pipeline with Jenkins, Nexus, Ant and Glassfish (Rob Terp) • Installing Java EE 6 SDK with Glassfish included on a VPS without GUI (jvm host) • GlassFish multimode Command for Batch Processing (javahowto) • Servlet Configuration in Servlet 3.0 api (Nikos Lianeris) • Creating a Simple Java Message Service (JMS) Producer with NetBeans and GlassFish (Oracle Learning Library) • GlassFish 3.1 to JBoss AS 7.1.1 EJB Invocation (java howto) • Tests In Java Ee For Zero-error Applications (Dylan Rodriguez) • Upgrading GlassFish 3.1.1 to 3.1.2 on Oracle Linux 6.2 64-bit (Matthias Hoys) • Migrating an Automated Deployment Script from Glassfish v2 to Glassfish v3 (Rob Terp) • Installer updates, Glassfish, Confluence and more…! (Rimu Hosting)

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• Concurrency Utilities for Java EE 6: JSR 236 Rebooting

  - by arungupta

  JSR 166 added support for concurrency utilities in the Java platform. The JSR 236's, a.k.a Concurrency Utilities for Java EE, goal was to extend that support to the Java EE platform by adding asynchronous abilities to different application components. The EG was however stagnant since Dec 2003. Its coming back to life with the co-spec lead Anthony Lai's message to the JSR 236 EG (archived here). The JSR will be operating under JCP 2.8's transparency rules and can be tracked at concurrency-spec.java.net. All the mailing lists are archived here. The final release is expected in Q1 2013 and the APIs will live in the javax.enterprise.concurrent package. Please submit your nomination if you would like to join this EG.

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• Non-blocking I/O using Servlet 3.1: Scalable applications using Java EE 7 (TOTD #188)

  - by arungupta

  Servlet 3.0 allowed asynchronous request processing but only traditional I/O was permitted. This can restrict scalability of your applications. In a typical application, ServletInputStream is read in a while loop. public class TestServlet extends HttpServlet {    protected void doGet(HttpServletRequest request, HttpServletResponse response)         throws IOException, ServletException {     ServletInputStream input = request.getInputStream();       byte[] b = new byte[1024];       int len = -1;       while ((len = input.read(b)) != -1) {          . . .        }   }} If the incoming data is blocking or streamed slower than the server can read then the server thread is waiting for that data. The same can happen if the data is written to ServletOutputStream. This is resolved in Servet 3.1 (JSR 340, to be released as part Java EE 7) by adding event listeners - ReadListener and WriteListener interfaces. These are then registered using ServletInputStream.setReadListener and ServletOutputStream.setWriteListener. The listeners have callback methods that are invoked when the content is available to be read or can be written without blocking. The updated doGet in our case will look like: AsyncContext context = request.startAsync();ServletInputStream input = request.getInputStream();input.setReadListener(new MyReadListener(input, context)); Invoking setXXXListener methods indicate that non-blocking I/O is used instead of the traditional I/O. At most one ReadListener can be registered on ServletIntputStream and similarly at most one WriteListener can be registered on ServletOutputStream. ServletInputStream.isReady and ServletInputStream.isFinished are new methods to check the status of non-blocking I/O read. ServletOutputStream.canWrite is a new method to check if data can be written without blocking.  MyReadListener implementation looks like: @Overridepublic void onDataAvailable() { try { StringBuilder sb = new StringBuilder(); int len = -1; byte b[] = new byte[1024]; while (input.isReady() && (len = input.read(b)) != -1) { String data = new String(b, 0, len); System.out.println("--> " + data); } } catch (IOException ex) { Logger.getLogger(MyReadListener.class.getName()).log(Level.SEVERE, null, ex); }}@Overridepublic void onAllDataRead() { System.out.println("onAllDataRead"); context.complete();}@Overridepublic void onError(Throwable t) { t.printStackTrace(); context.complete();} This implementation has three callbacks: onDataAvailable callback method is called whenever data can be read without blocking onAllDataRead callback method is invoked data for the current request is completely read. onError callback is invoked if there is an error processing the request. Notice, context.complete() is called in onAllDataRead and onError to signal the completion of data read. For now, the first chunk of available data need to be read in the doGet or service method of the Servlet. Rest of the data can be read in a non-blocking way using ReadListener after that. This is going to get cleaned up where all data read can happen in ReadListener only. The sample explained above can be downloaded from here and works with GlassFish 4.0 build 64 and onwards. The slides and a complete re-run of What's new in Servlet 3.1: An Overview session at JavaOne is available here. Here are some more references for you: Java EE 7 Specification Status Servlet Specification Project JSR Expert Group Discussion Archive Servlet 3.1 Javadocs

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• Server-Sent Events using GlassFish (TOTD #179)

  - by arungupta

  Bhakti blogged about Server-Sent Events on GlassFish and I've been planning to try it out for past some days. Finally, I took some time out today to learn about it and build a simplistic example showcasing the touch points. Server-Sent Events is developed as part of HTML5 specification and provides push notifications from a server to a browser client in the form of DOM events. It is defined as a cross-browser JavaScript API called EventSource. The client creates an EventSource by requesting a particular URL and registers an onmessage event listener to receive the event notifications. This can be done as shown var url = 'http://' + document.location.host + '/glassfish-sse/simple';eventSource = new EventSource(url);eventSource.onmessage = function (event) { var theParagraph = document.createElement('p'); theParagraph.innerHTML = event.data.toString(); document.body.appendChild(theParagraph);} This code subscribes to a URL, receives the data in the event listener, adds it to a HTML paragraph element, and displays it in the document. This is where you'll parse JSON and other processing to display if some other data format is received from the URL. The URL to which the EventSource is subscribed to is updated on the server side and there are multipe ways to do that. GlassFish 4.0 provide support for Server-Sent Events and it can be achieved registering a handler as shown below: @ServerSentEvent("/simple")public class MySimpleHandler extends ServerSentEventHandler { public void sendMessage(String data) { try { connection.sendMessage(data); } catch (IOException ex) { . . . } }} And then events can be sent to this handler using a singleton session bean as shown: @Startup@Statelesspublic class SimpleEvent { @Inject @ServerSentEventContext("/simple") ServerSentEventHandlerContext<MySimpleHandler> simpleHandlers; @Schedule(hour="*", minute="*", second="*/10") public void sendDate() { for(MySimpleHandler handler : simpleHandlers.getHandlers()) { handler.sendMessage(new Date().toString()); } }} This stateless session bean injects ServerSentEventHandlers listening on "/simple" path. Note, there may be multiple handlers listening on this path. The sendDate method triggers every 10 seconds and send the current timestamp to all the handlers. The client side browser simply displays the string. The HTTP request headers look like: Accept: text/event-streamAccept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3Accept-Encoding: gzip,deflate,sdchAccept-Language: en-US,en;q=0.8Cache-Control: no-cacheConnection: keep-aliveCookie: JSESSIONID=97ff28773ea6a085e11131acf47bHost: localhost:8080Referer: http://localhost:8080/glassfish-sse/faces/index2.xhtmlUser-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.54 Safari/536.5 And the response headers as: Content-Type: text/event-streamDate: Thu, 14 Jun 2012 21:16:10 GMTServer: GlassFish Server Open Source Edition 4.0Transfer-Encoding: chunkedX-Powered-By: Servlet/3.0 JSP/2.2 (GlassFish Server Open Source Edition 4.0 Java/Apple Inc./1.6) Notice, the MIME type of the messages from server to the client is text/event-stream and that is defined by the specification. The code in Bhakti's blog can be further simplified by using the recently-introduced Twitter API for Java as shown below: @Schedule(hour="*", minute="*", second="*/10") public void sendTweets() { for(MyTwitterHandler handler : twitterHandler.getHandlers()) { String result = twitter.search("glassfish", String.class); handler.sendMessage(result); }} The complete source explained in this blog can be downloaded here and tried on GlassFish 4.0 build 34. The latest promoted build can be downloaded from here and the complete source code for the API and implementation is here. I tried this sample on Chrome Version 19.0.1084.54 on Mac OS X 10.7.3.

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• LightView: JavaFX 2 real-time visualizer for GlassFish

  - by arungupta

  Adam Bien launched LightFish, a light-weight monitoring and visualization application for GlassFish. It comes with a introduction and a screencast to get you started. The tool provides monitoring information about threads and memory (such as heap size, thread count, peak thread count), transactions (commits and rollbacks), HTTP sessions, JDBC sessions, and even "paranormal activity". In a recently released first part of a tri-part article series at OTN, Adam explains how REST services can be exposed as bindable set of properties for JavaFX. The article titled "Enterprise side of JavaFX" shows how a practical combination of REST and JavaFX together. It explains how read-only and dynamic properties can be created. The fine-grained binding model allows clear separation of the view, presentation, and business logic. Read the first part here.

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• Configuring JMS and Message Queues in GlassFish - Sample Chapter

  - by arungupta

  PacktPub released Java EE 6 with GlassFish 3 Application Server a few months after the first version in GlassFish 3 train was released. This book is a practical guide to install and configure the GlassFish 3 Application Server and develop and deploy Java EE 6 applications on this server. Recently they released a sample chapter on how to configure JMS and message queues in GlassFish. The chapter provide complete snapshots from the web-based admin console and working sample code. The Table of Contents shows that all major Java EE 6 APIs and the details of the GlassFish 3 server are covered followed by examples of its use. This book is a practical guide with a very user-friendly approach. Read about other books on Java EE and GlassFish here.

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• Concurrency Utilities for Java EE Early Draft (JSR 236)

  - by arungupta

  Concurrency Utilities for Java EE is being worked as JSR 236 and has released an Early Draft. It provides concurrency capabilities to Java EE application components without compromising container integrity. Simple (common) and advanced concurrency patterns are easily supported without sacrificing usability. Using Java SE concurrency utilities such as java.util.concurrent API, java.lang.Thread and java.util.Timer in a Java EE application component such as EJB or Servlet are problematic since the container and server have no knowledge of these resources. JSR 236 enables concurrency largely by extending the Concurrency Utilities API developed under JSR-166. This also allows a consistency between Java SE and Java EE concurrency programming model. There are four main programming interfaces available: ManagedExecutorService ManagedScheduledExecutorService ContextService ManagedThreadFactory ManagedExecutorService is a managed version of java.util.concurrent.ExecutorService. The implementations of this interface are provided by the container and accessible using JNDI reference: <resource-env-ref>  <resource-env-ref-name>    concurrent/BatchExecutor  </resource-env-ref-name>  <resource-env-ref-type>    javax.enterprise.concurrent.ManagedExecutorService  </resource-env-ref-type><resource-env-ref> and available as: @Resource(name="concurrent/BatchExecutor")ManagedExecutorService executor; Its recommended to bind the JNDI references in the java:comp/env/concurrent subcontext. The asynchronous tasks that need to be executed need to implement java.lang.Runnable or java.util.concurrent.Callable interface as: public class MyTask implements Runnable { public void run() { // business logic goes here }} OR public class MyTask2 implements Callable<Date> {  public Date call() { // business logic goes here   }} The task is then submitted to the executor using one of the submit method that return a Future instance. The Future represents the result of the task and can also be used to check if the task is complete or wait for its completion. Future<String> future = executor.submit(new MyTask(), String.class);. . .String result = future.get(); Another example to submit tasks is: class MyTask implements Callback<Long> { . . . }class MyTask2 implements Callback<Date> { . . . }ArrayList<Callable> tasks = new ArrayList<();tasks.add(new MyTask());tasks.add(new MyTask2());List<Future<Object>> result = executor.invokeAll(tasks); The ManagedExecutorService may be configured for different properties such as: Hung Task Threshold: Time in milliseconds that a task can execute before it is considered hung Pool Info Core Size: Number of threads to keep alive Maximum Size: Maximum number of threads allowed in the pool Keep Alive: Time to allow threads to remain idle when # of threads > Core Size Work Queue Capacity: # of tasks that can be stored in inbound buffer Thread Use: Application intend to run short vs long-running tasks, accordingly pooled or daemon threads are picked ManagedScheduledExecutorService adds delay and periodic task running capabilities to ManagedExecutorService. The implementations of this interface are provided by the container and accessible using JNDI reference: <resource-env-ref>  <resource-env-ref-name>    concurrent/BatchExecutor  </resource-env-ref-name>  <resource-env-ref-type>    javax.enterprise.concurrent.ManagedExecutorService  </resource-env-ref-type><resource-env-ref> and available as: @Resource(name="concurrent/timedExecutor")ManagedExecutorService executor; And then the tasks are submitted using submit, invokeXXX or scheduleXXX methods. ScheduledFuture<?> future = executor.schedule(new MyTask(), 5, TimeUnit.SECONDS); This will create and execute a one-shot action that becomes enabled after 5 seconds of delay. More control is possible using one of the newly added methods: MyTaskListener implements ManagedTaskListener {  public void taskStarting(...) { . . . }  public void taskSubmitted(...) { . . . }  public void taskDone(...) { . . . }  public void taskAborted(...) { . . . } }ScheduledFuture<?> future = executor.schedule(new MyTask(), 5, TimeUnit.SECONDS, new MyTaskListener()); Here, ManagedTaskListener is used to monitor the state of a task's future. ManagedThreadFactory provides a method for creating threads for execution in a managed environment. A simple usage is: @Resource(name="concurrent/myThreadFactory")ManagedThreadFactory factory;. . .Thread thread = factory.newThread(new Runnable() { . . . }); concurrent/myThreadFactory is a JNDI resource. There is lot of interesting content in the Early Draft, download it, and read yourself. The implementation will be made available soon and also be integrated in GlassFish 4 as well. Some references for further exploring ... Javadoc Early Draft Specification concurrency-ee-spec.java.net [email protected]

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• What's new in EJB 3.2 ? - Java EE 7 chugging along!

  - by arungupta

  EJB 3.1 added a whole ton of features for simplicity and ease-of-use such as @Singleton, @Asynchronous, @Schedule, Portable JNDI name, EJBContainer.createEJBContainer, EJB 3.1 Lite, and many others. As part of Java EE 7, EJB 3.2 (JSR 345) is making progress and this blog will provide highlights from the work done so far. This release has been particularly kept small but include several minor improvements and tweaks for usability. More features in EJB.Lite Asynchronous session bean Non-persistent EJB Timer service This also means these features can be used in embeddable EJB container and there by improving testability of your application. Pruning - The following features were made Proposed Optional in Java EE 6 and are now made optional. EJB 2.1 and earlier Entity Bean Component Contract for CMP and BMP Client View of an EJB 2.1 and earlier Entity Bean EJB QL: Query Language for CMP Query Methods JAX-RPC-based Web Service Endpoints and Client View The optional features are moved to a separate document and as a result EJB specification is now split into Core and Optional documents. This allows the specification to be more readable and better organized. Updates and Improvements Transactional lifecycle callbacks in Stateful Session Beans, only for CMT. In EJB 3.1, the transaction context for lifecyle callback methods (@PostConstruct, @PreDestroy, @PostActivate, @PrePassivate) are defined as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Unspecified Unspecified Unspecified Unspecified Singleton Bean's transaction management type Bean's transaction management type N/A N/A In EJB 3.2, stateful session bean lifecycle callback methods can opt-in to be transactional. These methods are then executed in a transaction context as shown. @PostConstruct @PreDestroy @PrePassivate @PostActivate Stateless Unspecified Unspecified N/A N/A Stateful Bean's transaction management type Bean's transaction management type Bean's transaction management type Bean's transaction management type Singleton Bean's transaction management type Bean's transaction management type N/A N/A For example, the following stateful session bean require a new transaction to be started for @PostConstruct and @PreDestroy lifecycle callback methods. @Statefulpublic class HelloBean {   @PersistenceContext(type=PersistenceContextType.EXTENDED)   private EntityManager em;    @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)   @PostConstruct   public void init() {        myEntity = em.find(...);   }   @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)    @PostConstruct    public void destroy() {        em.flush();    }} Notice, by default the lifecycle callback methods are not transactional for backwards compatibility. They need to be explicitly opt-in to be made transactional. Opt-out of passivation for stateful session bean - If your stateful session bean needs to stick around or it has non-serializable field then the bean can be opt-out of passivation as shown. @Stateful(passivationCapable=false)public class HelloBean {    private NonSerializableType ref = ... . . .} Simplified the rules to define all local/remote views of the bean. For example, if the bean is defined as: @Statelesspublic class Bean implements Foo, Bar {    . . .} where Foo and Bar have no annotations of their own, then Foo and Bar are exposed as local views of the bean. The bean may be explicitly marked @Local as @Local@Statelesspublic class Bean implements Foo, Bar {    . . .} then this is the same behavior as explained above, i.e. Foo and Bar are local views. If the bean is marked @Remote as: @Remote@Statelesspublic class Bean implements Foo, Bar {    . . .} then Foo and Bar are remote views. If an interface is marked @Local or @Remote then each interface need to be explicitly marked explicitly to be exposed as a view. For example: @Remotepublic interface Foo { . . . }@Statelesspublic class Bean implements Foo, Bar {    . . .} only exposes one remote interface Foo. Section 4.9.7 from the specification provide more details about this feature. TimerService.getAllTimers is a newly added convenience API that returns all timers in the same bean. This is only for displaying the list of timers as the timer can only be canceled by its owner. Removed restriction to obtain the current class loader, and allow to use java.io package. This is handy if you want to do file access within your beans. JMS 2.0 alignment - A standard list of activation-config properties is now defined destinationLookup connectionFactoryLookup clientId subscriptionName shareSubscriptions Tons of other clarifications through out the spec. Appendix A provide a comprehensive list of changes since EJB 3.1. ThreadContext in Singleton is guaranteed to be thread-safe. Embeddable container implement Autocloseable. A complete replay of Enterprise JavaBeans Today and Tomorrow from JavaOne 2012 can be seen here (click on CON4654_mp4_4654_001 in Media). The specification is still evolving so the actual property or method names or their actual behavior may be different from the currently proposed ones. Are there any improvements that you'd like to see in EJB 3.2 ? The EJB 3.2 Expert Group would love to hear your feedback. An Early Draft of the specification is available. The latest version of the specification can always be downloaded from here. Java EE 7 Specification Status EJB Specification Project JIRA of EJB Specification JSR Expert Group Discussion Archive These features will start showing up in GlassFish 4 Promoted Builds soon.

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• Collaborative Whiteboard using WebSocket in GlassFish 4 - Text/JSON and Binary/ArrayBuffer Data Transfer (TOTD #189)

  - by arungupta

  This blog has published a few blogs on using JSR 356 Reference Implementation (Tyrus) as its integrated in GlassFish 4 promoted builds. TOTD #183: Getting Started with WebSocket in GlassFish TOTD #184: Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket TOTD #186: Custom Text and Binary Payloads using WebSocket One of the typical usecase for WebSocket is online collaborative games. This Tip Of The Day (TOTD) explains a sample that can be used to build such games easily. The application is a collaborative whiteboard where different shapes can be drawn in multiple colors. The shapes drawn on one browser are automatically drawn on all other peer browsers that are connected to the same endpoint. The shape, color, and coordinates of the image are transfered using a JSON structure. A browser may opt-out of sharing the figures. Alternatively any browser can send a snapshot of their existing whiteboard to all other browsers. Take a look at this video to understand how the application work and the underlying code. The complete sample code can be downloaded here. The code behind the application is also explained below. The web page (index.jsp) has a HTML5 Canvas as shown: <canvas id="myCanvas" width="150" height="150" style="border:1px solid #000000;"></canvas> And some radio buttons to choose the color and shape. By default, the shape, color, and coordinates of any figure drawn on the canvas are put in a JSON structure and sent as a message to the WebSocket endpoint. The JSON structure looks like: { "shape": "square", "color": "#FF0000", "coords": { "x": 31.59999942779541, "y": 49.91999053955078 }} The endpoint definition looks like: @WebSocketEndpoint(value = "websocket",encoders = {FigureDecoderEncoder.class},decoders = {FigureDecoderEncoder.class})public class Whiteboard { As you can see, the endpoint has decoder and encoder registered that decodes JSON to a Figure (a POJO class) and vice versa respectively. The decode method looks like: public Figure decode(String string) throws DecodeException { try { JSONObject jsonObject = new JSONObject(string); return new Figure(jsonObject); } catch (JSONException ex) { throw new DecodeException("Error parsing JSON", ex.getMessage(), ex.fillInStackTrace()); }} And the encode method looks like: public String encode(Figure figure) throws EncodeException { return figure.getJson().toString();} FigureDecoderEncoder implements both decoder and encoder functionality but thats purely for convenience. But the recommended design pattern is to keep them in separate classes. In certain cases, you may even need only one of them. On the client-side, the Canvas is initialized as: var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");canvas.addEventListener("click", defineImage, false); The defineImage method constructs the JSON structure as shown above and sends it to the endpoint using websocket.send(). An instant snapshot of the canvas is sent using binary transfer with WebSocket. The WebSocket is initialized as: var wsUri = "ws://localhost:8080/whiteboard/websocket";var websocket = new WebSocket(wsUri);websocket.binaryType = "arraybuffer"; The important part is to set the binaryType property of WebSocket to arraybuffer. This ensures that any binary transfers using WebSocket are done using ArrayBuffer as the default type seem to be blob. The actual binary data transfer is done using the following: var image = context.getImageData(0, 0, canvas.width, canvas.height);var buffer = new ArrayBuffer(image.data.length);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = image.data[i];}websocket.send(bytes); This comprehensive sample shows the following features of JSR 356 API: Annotation-driven endpoints Send/receive text and binary payload in WebSocket Encoders/decoders for custom text payload In addition, it also shows how images can be captured and drawn using HTML5 Canvas in a JSP. How could this be turned in to an online game ? Imagine drawing a Tic-tac-toe board on the canvas with two players playing and others watching. Then you can build access rights and controls within the application itself. Instead of sending a snapshot of the canvas on demand, a new peer joining the game could be automatically transferred the current state as well. Do you want to build this game ? I built a similar game a few years ago. Do somebody want to rewrite the game using WebSocket APIs ? :-) Many thanks to Jitu and Akshay for helping through the WebSocket internals! Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• Petstore using Java EE 6 ? Almost!

  - by arungupta

  Antonio Goncalves, a Java Champion, JUG leader, and a well-known author, has started building a Petstore-like application using Java EE 6. The complete end-to-end sample application will build a eCommerce website and follows the Java EE 6 design principles of simple and easy-to-use to its core. Its using several technologies from the platform such as JPA 2.0, CDI 1.0, Bean Validation 1.0, EJB Lite 3.1, JSF 2.0, and JAX-RS 1.1. The two goals of the project are: • use Java EE 6 and just Java EE 6 : no external framework or dependency • make it simple : no complex business algorithm The application works with GlassFish and JBoss today and there are plans to add support for TomEE. Download the source code from github.com/agoncal/agoncal-application-petstore-ee6. And feel free to fork if you want to use a fancy toolkit as the front-end or show some nicer back-end integration. Some other sources of similar end-to-end applications are: • Java EE 6 Tutorial • Java EE 6 Galleria • Java EE 6 Hands-on Lab

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• Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket - (TOTD #185)

  - by arungupta

  The WebSocket API defines different send(xxx) methods that can be used to send text and binary data. This Tip Of The Day (TOTD) will show how to send and receive text and binary data using WebSocket. TOTD #183 explains how to get started with a WebSocket endpoint using GlassFish 4. A simple endpoint from that blog looks like: @WebSocketEndpoint("/endpoint") public class MyEndpoint { public void receiveTextMessage(String message) { . . . } } A message with the first parameter of the type String is invoked when a text payload is received. The payload of the incoming WebSocket frame is mapped to this first parameter. An optional second parameter, Session, can be specified to map to the "other end" of this conversation. For example: public void receiveTextMessage(String message, Session session) {     . . . } The return type is void and that means no response is returned to the client that invoked this endpoint. A response may be returned to the client in two different ways. First, set the return type to the expected type, such as: public String receiveTextMessage(String message) { String response = . . . . . . return response; } In this case a text payload is returned back to the invoking endpoint. The second way to send a response back is to use the mapped session to send response using one of the sendXXX methods in Session, when and if needed. public void receiveTextMessage(String message, Session session) {     . . .     RemoteEndpoint remote = session.getRemote();     remote.sendString(...);     . . .     remote.sendString(...);    . . .    remote.sendString(...); } This shows how duplex and asynchronous communication between the two endpoints can be achieved. This can be used to define different message exchange patterns between the client and server. The WebSocket client can send the message as: websocket.send(myTextField.value); where myTextField is a text field in the web page. Binary payload in the incoming WebSocket frame can be received if ByteBuffer is used as the first parameter of the method signature. The endpoint method signature in that case would look like: public void receiveBinaryMessage(ByteBuffer message) {     . . . } From the client side, the binary data can be sent using Blob, ArrayBuffer, and ArrayBufferView. Blob is a just raw data and the actual interpretation is left to the application. ArrayBuffer and ArrayBufferView are defined in the TypedArray specification and are designed to send binary data using WebSocket. In short, ArrayBuffer is a fixed-length binary buffer with no format and no mechanism for accessing its contents. These buffers are manipulated using one of the views defined by one of the subclasses of ArrayBufferView listed below: Int8Array (signed 8-bit integer or char) Uint8Array (unsigned 8-bit integer or unsigned char) Int16Array (signed 16-bit integer or short) Uint16Array (unsigned 16-bit integer or unsigned short) Int32Array (signed 32-bit integer or int) Uint32Array (unsigned 16-bit integer or unsigned int) Float32Array (signed 32-bit float or float) Float64Array (signed 64-bit float or double) WebSocket can send binary data using ArrayBuffer with a view defined by a subclass of ArrayBufferView or a subclass of ArrayBufferView itself. The WebSocket client can send the message using Blob as: blob = new Blob([myField2.value]);websocket.send(blob); where myField2 is a text field in the web page. The WebSocket client can send the message using ArrayBuffer as: var buffer = new ArrayBuffer(10);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = i;}websocket.send(buffer); A concrete implementation of receiving the binary message may look like: @WebSocketMessagepublic void echoBinary(ByteBuffer data, Session session) throws IOException {    System.out.println("echoBinary: " + data);    for (byte b : data.array()) {        System.out.print(b);    }    session.getRemote().sendBytes(data);} This method is just printing the binary data for verification but you may actually be storing it in a database or converting to an image or something more meaningful. Be aware of TYRUS-51 if you are trying to send binary data from server to client using method return type. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Custom payloads using encoder/decoder Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• Java EE 7 support in NetBeans 7.3.1

  - by arungupta

  NetBeans IDE provide tools, templates, and samples for building Java EE 7 applications. NetBeans 7.3.1 specifically added support for the features mentioned below: Support for creating Java EE 7 projects using Maven and Ant Develop, Deploy, and Debug using GlassFish 4 Bundled Java EE 7 javadocs CDI is enabled by default for new Java EE 7 projects (CDI 1.1) Create database scripts from Entity Classes (JPA 2.1) Java Persistence Query Language (JPQL) testing tool (JPA 2.1) RESTful Java client creation using JAX-RS 2.0 Client APIs (JAX-RS 2.0) New templates for JAX-RS 2 Filter and Interceptor (JAX-RS 2.0) New templates for WebSocket endpoints (WebSocket 1.0) JMS messages are sent using JMS 2 simplified API (JMS 2.0) Pass-through attributes are supported during Facelet page editing (JSF 2.2) Resource Library Contracts(JSF 2.2) @FlowScoped beans from editor and wizards (JSF 2.2) Support for EL 3.0 syntax in editor (EL 3.0) JSON APIs can be used with code completion (JSON 1.0) A comprehensive list of features added in this release is available in NetBeans 7.3.1 New and Noteworthy. Watch the screencast below to get a quick overview of the features and capabilities: Download Netbeans 7.3.1 and start playing with Java EE 7!

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• What's new in Servlet 3.1 ? - Java EE 7 moving forward

  - by arungupta

  Servlet 3.0 was released as part of Java EE 6 and made huge changes focused at ease-of-use. The idea was to leverage the latest language features such as annotations and generics and modernize how Servlets can be written. The web.xml was made as optional as possible. Servet 3.1 (JSR 340), scheduled to be part of Java EE 7, is an incremental release focusing on couple of key features and some clarifications in the specification. The main features of Servlet 3.1 are explained below: Non-blocking I/O - Servlet 3.0 allowed asynchronous request processing but only traditional I/O was permitted. This can restrict scalability of your applications. Non-blocking I/O allow to build scalable applications. TOTD #188 provide more details about how non-blocking I/O can be done using Servlet 3.1. HTTP protocol upgrade mechanism - Section 14.42 in the HTTP 1.1 specification (RFC 2616) defines an upgrade mechanism that allows to transition from HTTP 1.1 to some other, incompatible protocol. The capabilities and nature of the application-layer communication after the protocol change is entirely dependent upon the new protocol chosen. After an upgrade is negotiated between the client and the server, the subsequent requests use the new chosen protocol for message exchanges. A typical example is how WebSocket protocol is upgraded from HTTP as described in Opening Handshake section of RFC 6455. The decision to upgrade is made in Servlet.service method. This is achieved by adding a new method: HttpServletRequest.upgrade and two new interfaces: javax.servlet.http.HttpUpgradeHandler and javax.servlet.http.WebConnection. TyrusHttpUpgradeHandler shows how WebSocket protocol upgrade is done in Tyrus (Reference Implementation for Java API for WebSocket). Security enhancements Applying run-as security roles to #init and #destroy methods Session fixation attack by adding HttpServletRequest.changeSessionId and a new interface HttpSessionIdListener. You can listen for any session id changes using these methods. Default security semantic for non-specified HTTP method in <security-constraint> Clarifying the semantics if a parameter is specified in the URI and payload Miscellaneous ServletResponse.reset clears any data that exists in the buffer as well as the status code, headers. In addition, Servlet 3.1 will also clears the state of calling getServletOutputStream or getWriter. ServletResponse.setCharacterEncoding: Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8. Relative protocol URL can be specified in HttpServletResponse.sendRedirect. This will allow a URL to be specified without a scheme. That means instead of specifying "http://anotherhost.com/foo/bar.jsp" as a redirect address, "//anotherhost.com/foo/bar.jsp" can be specified. In this case the scheme of the corresponding request will be used. Clarification in HttpServletRequest.getPart and .getParts without multipart configuration. Clarification that ServletContainerInitializer is independent of metadata-complete and is instantiated per web application. A complete replay of What's New in Servlet 3.1: An Overview from JavaOne 2012 can be seen here (click on CON6793_mp4_6793_001 in Media). Each feature will be added to the JSR subject to EG approval. You can share your feedback to [email protected]. Here are some more references for you: Servlet 3.1 Public Review Candidate Downloads Servlet 3.1 PR Candidate Spec Servlet 3.1 PR Candidate Javadocs Servlet Specification Project JSR Expert Group Discussion Archive Java EE 7 Specification Status Several features have already been integrated in GlassFish 4 Promoted Builds. Have you tried any of them ? Here are some other Java EE 7 primers published so far: Concurrency Utilities for Java EE (JSR 236) Collaborative Whiteboard using WebSocket in GlassFish 4 (TOTD #189) Non-blocking I/O using Servlet 3.1 (TOTD #188) What's New in EJB 3.2 ? JPA 2.1 Schema Generation (TOTD #187) WebSocket Applications using Java (JSR 356) Jersey 2 in GlassFish 4 (TOTD #182) WebSocket and Java EE 7 (TOTD #181) Java API for JSON Processing (JSR 353) JMS 2.0 Early Draft (JSR 343) And of course, more on their way! Do you want to see any particular one first ?

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• Silicon Valley Code Camp 2012 - Submit Your Talks

  - by arungupta

  Silicon Valley Code Camp follows three rules: Given by/for the community Always free Never occur during work hours I've spoken there at 2011, 2010, 2009, 2008, and 2007 and have again submitted a talk this year as well, and will submit more! Its one of the best organically grown code camps with the attendance constantly growing over the past 6 years. Here is a chart that shows how the number of conferences attendees that registered and attended and the sessions delivered over past 6 years. If you wonder why there is such a big gap between "registered" and "attended" that's because this event is FREE! Yes, 100% free. If you are in and around Silicon Valley then you have no reason to not participate/speak at SVCC. You have the opportunity to meet all the local JUG leaders and the community "rockstars" :-) Date: Oct 6/7, 2012 Venue: Foothill College, 12345, El Monte Road, Los Altos Hills, CA Submit today or register!

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• Migrating Spring to Java EE 6 Article Series at OTN - Part 3

  - by arungupta

  The spring season is characterized by migration of birds, whales, butterflies, frogs, and other animals for different reasons. If you use Spring framework and are interested in migrating to a standards-based Java EE platform, for whatever reason, then we have a solution for you. David Heffelfinger's, a renowned author and an ardent Java EE fan, has published third part of Spring to Java EE migration series at OTN. The article series takes a typical Spring application and shows how to migrate it to Java EE 6 using NetBeans. This new part builds upon part 1 and part 2 and also compares the generated WAR files and LoC in XML configuration in the two environments. There is an interesting discussion on Why Java EE 6 over Spring ? as well.

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• Hands-on GlassFish FREE Course covering Deployment, Class Loading, Clustering, etc.

  - by arungupta

  René van Wijk, an Oracle ACE Director and a prolific blogger at middlewaremagic.com has shared contents of a FREE hands-on course on GlassFish. The course provides an introduction to GlassFish internals, JVM tuning, Deployment, Class Loading, Security, Resource Configuration, and Clustering. The self-paced hands-on instructions guide through the process of installing, configuring, deploying, tuning and other aspects of application development and deployment on GlassFish. The complete course material is available here. This course can also be taken as a paid instructor-led course. The attendees will get their own VM and will have plenty of time for Q&A and discussions. Register for this paid course. Oracle Education also offers a similar paid course on Oracle GlassFish Server 3.1: Administration and Deployment.

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• Custom Text and Binary Payloads using WebSocket (TOTD #186)

  - by arungupta

  TOTD #185 explained how to process text and binary payloads in a WebSocket endpoint. In summary, a text payload may be received as public void receiveTextMessage(String message) {    . . . } And binary payload may be received as: public void recieveBinaryMessage(ByteBuffer message) {    . . .} As you realize, both of these methods receive the text and binary data in raw format. However you may like to receive and send the data using a POJO. This marshaling and unmarshaling can be done in the method implementation but JSR 356 API provides a cleaner way. For encoding and decoding text payload into POJO, Decoder.Text (for inbound payload) and Encoder.Text (for outbound payload) interfaces need to be implemented. A sample implementation below shows how text payload consisting of JSON structures can be encoded and decoded. public class MyMessage implements Decoder.Text<MyMessage>, Encoder.Text<MyMessage> {     private JsonObject jsonObject;    @Override    public MyMessage decode(String string) throws DecodeException {        this.jsonObject = new JsonReader(new StringReader(string)).readObject();               return this;    }     @Override    public boolean willDecode(String string) {        return true;    }     @Override    public String encode(MyMessage myMessage) throws EncodeException {        return myMessage.jsonObject.toString();    } public JsonObject getObject() { return jsonObject; }} In this implementation, the decode method decodes incoming text payload to MyMessage, the encode method encodes MyMessage for the outgoing text payload, and the willDecode method returns true or false if the message can be decoded. The encoder and decoder implementation classes need to be specified in the WebSocket endpoint as: @WebSocketEndpoint(value="/endpoint", encoders={MyMessage.class}, decoders={MyMessage.class}) public class MyEndpoint { public MyMessage receiveMessage(MyMessage message) { . . . } } Notice the updated method signature where the application is working with MyMessage instead of the raw string. Note that the encoder and decoder implementations just illustrate the point and provide no validation or exception handling. Similarly Encooder.Binary and Decoder.Binary interfaces need to be implemented for encoding and decoding binary payload. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• JVM Language Summit 2012 - Registration Open

  - by arungupta

  The 2012 edition of the JVM Languages Summit is Jul 30 - Aug 1, at Oracle's Santa Clara Campus. This is an "an open technical collaboration among language designers, compiler writers, tool builders, runtime engineers, and VM architects". There are presentations, workshops, and lightning talks. About 70 language and VM implementers attended last year and the talks were recorded. Some videos from last year are available here. Check out the Main Page, the Agenda, Logistics, and the Wiki. See the Registration Online; for questions, send mail to inquire AT jvmlangsummit.com.

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• Jersey 2.0 Milestone 2 Now Available

  - by arungupta

  Jersey 2.0 milestone 2 is now available. It builds upon the first milestone and adds several new features such as server-side asynchronous processing, server-side content negotiation, improved JAX-RS parameter injection, and several others. The REST endpoints can be published on Java SE HTTP Server, Grizzly 2 HTTP container, and some basic Servlet-based deployments. It also provides HTTPURLConnection-based client API implementation. Read about these and more about what's new in Marek's detailed post. Of course this is also the future reference implementation for JAX-RS 2.0. Feel like trying it out? Simply go to Maven Central (of course none of this is production quality at this point). The latest JAX-RS Javadocs and Jersey 2.0 API docs are good starting points to explore. And provide them feedback at [email protected].

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