A slowdown in the Oracle RAC cluster degraded an entire application’s response time. Here, let’s discuss the steps we pursued to troubleshoot this problem.
JavaZone is my absolute favorite Java conference. I like it even more than JavaOne at Moscone! Great to be back to enjoy great content, food, and company.
A closer look at Java at Microsoft and Azure and what Microsoft can offer to modernize existing Java-based apps or bring new ones with the practice of IaC
Learn about a new framework that allows processing methods asynchronously with retries in case of failure and the support of load-balancing and failover.
for people in hurry, here is the code and some steps to run few demo samples . disclaimer: i am still learning play 2.0, please point to me if something is incorrect. play 2.0 is a web application stack that bundled with netty for http server , akka for loosely coupled backend processing and comet / websocket for asynchronous browser rendering. play 2.0 itself does not do any session state management, but uses cookies to manage user sessions and flash data . play 2.0 advocates reactive model based on iteratee io . please also see my blog on how play 2.0 pits against spring mvc . in this blog, i will discuss some of these points and also discuss how akka and comet complement play 2.0. the more i understand play 2.0 stack the more i realize that scala is better suited to take advantages of capabilities of play 2.0 compared to java. there is a blog on how web developers view of play 2.0 . you can understand how akka’s actor pits against jms refer this stackoverflow writeup . a good documentation on akka’s actor is here . play 2.0, netty, akka, commet: how it fits play 2.0, netty, akka, comet: how it fits servlet container like tomcat blocks each request until the backend processing is complete. play 2.0 stack will help in achieving the usecase like, you need to web crawl and get all the product listing from various sources in a non-blocking and asynchronous way using loosely coupled message oriented architecture. for example, the below code will not be scalable in play 2.0 stack, because play has only 1 main thread and the code blocks other requests to be processed. in play 2.0/netty the application registers with callback on a long running process using frameworks like akka when it is completed, in a reactive pattern. public static result index() { //here is where you can put your long running blocking code like getting // the product feed from various sources return ok("hello world"); } the controller code to use akka to work in a non-blocking way with async callback is as below, public static result index() { return async( future(new callable() { public integer call() { //here is where you can put your long running blocking code like getting //the product feed from various sources return 4; } }).map(new function() { public result apply(integer i) { objectnode result = json.newobject(); result.put("id", i); return ok(result); } }) ); } and more cleaner and preferred way is akka’s actor model is as below, public static result sayhello(string data) { logger.debug("got the request: {}" + data); actorsystem system = actorsystem.create("mysystem"); actorref myactor = system.actorof(new props(myuntypedactor.class), "myactor"); return async( akka.aspromise(ask(myactor, data, 1000)).map( new function() { public result apply(object response) { objectnode result = json.newobject(); result.put("message", response.tostring()); return ok(result); } } ) ); } static public class myuntypedactor extends untypedactor { public void onreceive(object message) throws exception { if (message instanceof string){ logger.debug("received string message: {}" + message); //here is where you can put your long running blocking code like getting //the product feed from various sources getsender().tell("hello world"); } else { unhandled(message); } } } f you want to understand how we can use comet for asynchronously render data to the browser using play, akka and comet refer the code in github . here is some good writeup comparing comet and websocket in stackoverflow .
I have talked about human filters and my plan for digital curation. These items are the fruits of those ideas, the items I deemed worthy from my Google Reader feeds. These items are a combination of tech business news, development news and programming tools and techniques. Making accessible icon buttons (NCZOnline) Double Shot #1097 (A Fresh Cup) Life Beyond Rete – R.I.P Rete 2013 (Java Code Geeks) My Passover Project: Introducing Rattlesnake.CLR (Ayende @ Rahien) Super useful jQuery plugins for responsive web design (HTML5 Zone) Android Development – Your First Steps (Javalobby – The heart of the Java developer community) Never Ever Rewrite Your System (Javalobby – The heart of the Java developer community) Telecommuting, Hoteling, and Managing Product Development (Javalobby – The heart of the Java developer community) The Daily Six Pack: April 1, 2013 (Dirk Strauss) Optimizing Proto-Geeks for Business (DaedTech) Learning Bootstrap Part 2: Working with Buttons (debug mode……) Rumination on Time (Rob Williams' Blog) Unit-Testing Multi-Threaded Code Timers (Architects Zone – Architectural Design Patterns & Best Practices) Metrics for Agile (Javalobby – The heart of the Java developer community) Detecting Java Threads in Deadlock with Groovy and JMX (Inspired by Actual Events) Entrepreneurs: Stop participating in hackathons just to win them (VentureBeat) How to hack the recruitment process to find the best developers for your startup or agency (The Next Web) Hardware Hacks: MongoLab + Arduino (Architects Zone – Architectural Design Patterns & Best Practices) The Daily Six Pack: March 30, 2013 (Dirk Strauss) I hope you enjoy today’s items, and please participate in the discussions on those sites.
I have talked about human filters and my plan for digital curation. These items are the fruits of those ideas, the items I deemed worthy from my Google Reader feeds. These items are a combination of tech business news, development news and programming tools and techniques. Dew Drop – June 7, 2013 (#1,563) (Alvin Ashcraft's Morning Dew) On friction in software (Ayende @ Rahien) Caching, jQuery Ajax and Other IE Fun (HTML5 Zone) IndexedDB and Date Example (HTML5 Zone) DevOps Scares Me – Part 1 (Architects Zone – Architectural Design Patterns & Best Practices) Visualizing the News with Vivagraph.js (Architects Zone – Architectural Design Patterns & Best Practices) My First Clojure Workflow (Javalobby – The heart of the Java developer community) Helping an ISV Look at Their Cloud Options (Architects Zone – Architectural Design Patterns & Best Practices) Ignore Requirements to Gain Flexibility, Value, Insights! The Power of Why (Javalobby – The heart of the Java developer community) Estimating the Unknown: Dates or Budgets, Part 1 (Agile Zone – Software Methodologies for Development Managers) Team Decision Making Techniques – Fist to Five and others (Agile Zone – Software Methodologies for Development Managers) The Daily Six Pack: June 7, 2013 (Dirk Strauss) Pastime (xkcd.com) The Affect Heuristic (Mark Needham) Every great company has been built the same way: bit by bit (Hacker News) Under the Hood: The entities graph (Facebook Engineering's Facebook Notes) Entrepreneurship With a Family is for Crazy People (Stay N Alive) Thinking Together for Release Planning (Javalobby – The heart of the Java developer community) I hope you enjoy today’s items, and please participate in the discussions on those sites.
Poor Oddjob, I thought as I read Craig Flichel’s Feature Comparison of Java Job Schedulers featuring Obsidian, Quartz, Cron4j and Spring. Yet again it hasn’t made the grade, it’s been passed over for the scheduling team. Never mind I say, you’re just a little bit different and misunderstood. Let’s have a kick about in the back yard and see what you can do… Real-time Schedule Changes / Real-time Job Configuration Oddjob: Yes Here is Oddjob’s Client GUI, connecting to an instance of Oddjob running as a Windows Service on my home PC. My Oddob instance sends me a reminder email when it’s someone’s birthday, and also tells me when it’s going to rain. The swing UI allows complete configuration of the server. With it I can configure the jobs and their schedules, but unfortunately I can’t control the weather! Ad-hoc Job Submission: Yes Configurable Job Conflicts: Not Really Applicable Ad-hoc job submission is really what Oddjob is all about. Many jobs won’t be scheduled at all and will sit in a folder to be manually run as required. To run a job, scheduled or not, just click ‘run’ from the job menu. Job conflicts aren’t really a problem for Oddjob because it won’t reschedule a job again until it’s finished. If a job’s next slot has passed, you have the choice to run immediately or skip missed runs and reschedule from the current time. If you want concurrent execution you can configure different jobs to run at the same time or use a single schedule and launch the jobs in parallel. Manually Stopping a job is just as easy as running it. Click ‘stop’ from the job menu. Code- and XML-Free Job Configuration Oddjob: Yes You saw this in the first section. Oddjob’s configuration is via a UI and is done in real time. In fact I often start one job as I’m configuring the next. It’s all very interactive. Oddjob uses XML behind the scenes for those that like to see under the hood. Job Event Subscription/Notification Oddjob: Yes It’s very easy to trigger a job based on the completion state of another job. You would have to write code to listen to configuration changes though. Custom Listeners: Undocumented Job Chaining: Yes There’s lots of options for job chaining, sequential, parallel, or cascade, and any nested combinations thereof. Adding a custom Stateful listener would be easy enough, and might be useful if embedding Oddjob but this isn’t the normal use case. The unit tests do this extensively however. Monitoring & Management UI Oddjob: Yes The same UI allows you to see the job state, job by job log messages, the console of an Exec Job, and the run time properties of all the jobs. Zero Configuration Clustering and Load Sharing Oddjob: Kind Of Oddjob has a Grab Job so you can run the same configuration on several servers and have them compete for work. I wrote it as a proof of concept but I’ve never had cause to use it in the field and I haven’t had any reports that others have either. Job Execution Host Affinity: Kind Of In the same way that you add the ‘Grab job’ to many servers to share work, you could in theory just add Grab for a particular job to only certain servers. I guess this is server Affinity? Scripting Language Support in Jobs Oddjob: Yes Oddjob has a Script Job for any language that supports the Java Scripting Framework. JavaScript is shipped by default.With the Script Job you can also interact with Oddjob to use the properties of other jobs, and set variables for other jobs to use. Scheduling Precision Oddjob: Millisecond In theory Oddjob can schedule with millisecond precision, but this isn’t usual practice. Polling for a file every 30 seconds, for instance, is normally fine. Job Scheduling & Management REST API Oddjob: JMX Only No REST API. You can embed the JMX Client easily enough and control everything from Java, but not for other languages. Not yet. Custom Calendar Support Oddjob: Yes Oddjob has the concept of breaking a schedule with another. The breaks can be as flexible as the job schedule itself – define days, weeks or just a few hours off for a task. The Scheduling section of the User Guide has much more on Oddjob’s flexible scheduling capabilities. Conclusion Oddjob has many other features to make automating repetitive tasks easy. One noteworthy feature is the ease of adding custom jobs by just implementing java.lang.Runnable. Oddjob is undeniably an amateur player in the Scheduler league, and one that is often overlooked. With its Apache licence it is completely free and open. Why not check it out when you have an hour or two? You might be pleasantly surprised by the quality of play.
We will discuss transaction management in Java; we should know what a transaction is; therefore, the following are some important points about the transaction.
Here's how to start using Cucumber, the widely used BDD framework for Selenium automation testing. This article helps you get set up in Eclipse and IntelliJ IDEA. It also provides a step-by-step guide on setting up Maven Cucumber project in Eclipse.
