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  • Parallel Classloading Revisited: Fully Concurrent Loading

    - by davidholmes
    Java 7 introduced support for parallel classloading. A description of that project and its goals can be found here: http://openjdk.java.net/groups/core-libs/ClassLoaderProposal.html The solution for parallel classloading was to add to each class loader a ConcurrentHashMap, referenced through a new field, parallelLockMap. This contains a mapping from class names to Objects to use as a classloading lock for that class name. This was then used in the following way: protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException { synchronized (getClassLoadingLock(name)) { // First, check if the class has already been loaded Class c = findLoadedClass(name); if (c == null) { long t0 = System.nanoTime(); try { if (parent != null) { c = parent.loadClass(name, false); } else { c = findBootstrapClassOrNull(name); } } catch (ClassNotFoundException e) { // ClassNotFoundException thrown if class not found // from the non-null parent class loader } if (c == null) { // If still not found, then invoke findClass in order // to find the class. long t1 = System.nanoTime(); c = findClass(name); // this is the defining class loader; record the stats sun.misc.PerfCounter.getParentDelegationTime().addTime(t1 - t0); sun.misc.PerfCounter.getFindClassTime().addElapsedTimeFrom(t1); sun.misc.PerfCounter.getFindClasses().increment(); } } if (resolve) { resolveClass(c); } return c; } } Where getClassLoadingLock simply does: protected Object getClassLoadingLock(String className) { Object lock = this; if (parallelLockMap != null) { Object newLock = new Object(); lock = parallelLockMap.putIfAbsent(className, newLock); if (lock == null) { lock = newLock; } } return lock; } This approach is very inefficient in terms of the space used per map and the number of maps. First, there is a map per-classloader. As per the code above under normal delegation the current classloader creates and acquires a lock for the given class, checks if it is already loaded, then asks its parent to load it; the parent in turn creates another lock in its own map, checks if the class is already loaded and then delegates to its parent and so on till the boot loader is invoked for which there is no map and no lock. So even in the simplest of applications, you will have two maps (in the system and extensions loaders) for every class that has to be loaded transitively from the application's main class. If you knew before hand which loader would actually load the class the locking would only need to be performed in that loader. As it stands the locking is completely unnecessary for all classes loaded by the boot loader. Secondly, once loading has completed and findClass will return the class, the lock and the map entry is completely unnecessary. But as it stands, the lock objects and their associated entries are never removed from the map. It is worth understanding exactly what the locking is intended to achieve, as this will help us understand potential remedies to the above inefficiencies. Given this is the support for parallel classloading, the class loader itself is unlikely to need to guard against concurrent load attempts - and if that were not the case it is likely that the classloader would need a different means to protect itself rather than a lock per class. Ultimately when a class file is located and the class has to be loaded, defineClass is called which calls into the VM - the VM does not require any locking at the Java level and uses its own mutexes for guarding its internal data structures (such as the system dictionary). The classloader locking is primarily needed to address the following situation: if two threads attempt to load the same class, one will initiate the request through the appropriate loader and eventually cause defineClass to be invoked. Meanwhile the second attempt will block trying to acquire the lock. Once the class is loaded the first thread will release the lock, allowing the second to acquire it. The second thread then sees that the class has now been loaded and will return that class. Neither thread can tell which did the loading and they both continue successfully. Consider if no lock was acquired in the classloader. Both threads will eventually locate the file for the class, read in the bytecodes and call defineClass to actually load the class. In this case the first to call defineClass will succeed, while the second will encounter an exception due to an attempted redefinition of an existing class. It is solely for this error condition that the lock has to be used. (Note that parallel capable classloaders should not need to be doing old deadlock-avoidance tricks like doing a wait() on the lock object\!). There are a number of obvious things we can try to solve this problem and they basically take three forms: Remove the need for locking. This might be achieved by having a new version of defineClass which acts like defineClassIfNotPresent - simply returning an existing Class rather than triggering an exception. Increase the coarseness of locking to reduce the number of lock objects and/or maps. For example, using a single shared lockMap instead of a per-loader lockMap. Reduce the lifetime of lock objects so that entries are removed from the map when no longer needed (eg remove after loading, use weak references to the lock objects and cleanup the map periodically). There are pros and cons to each of these approaches. Unfortunately a significant "con" is that the API introduced in Java 7 to support parallel classloading has essentially mandated that these locks do in fact exist, and they are accessible to the application code (indirectly through the classloader if it exposes them - which a custom loader might do - and regardless they are accessible to custom classloaders). So while we can reason that we could do parallel classloading with no locking, we can not implement this without breaking the specification for parallel classloading that was put in place for Java 7. Similarly we might reason that we can remove a mapping (and the lock object) because the class is already loaded, but this would again violate the specification because it can be reasoned that the following assertion should hold true: Object lock1 = loader.getClassLoadingLock(name); loader.loadClass(name); Object lock2 = loader.getClassLoadingLock(name); assert lock1 == lock2; Without modifying the specification, or at least doing some creative wordsmithing on it, options 1 and 3 are precluded. Even then there are caveats, for example if findLoadedClass is not atomic with respect to defineClass, then you can have concurrent calls to findLoadedClass from different threads and that could be expensive (this is also an argument against moving findLoadedClass outside the locked region - it may speed up the common case where the class is already loaded, but the cost of re-executing after acquiring the lock could be prohibitive. Even option 2 might need some wordsmithing on the specification because the specification for getClassLoadingLock states "returns a dedicated object associated with the specified class name". The question is, what does "dedicated" mean here? Does it mean unique in the sense that the returned object is only associated with the given class in the current loader? Or can the object actually guard loading of multiple classes, possibly across different class loaders? So it seems that changing the specification will be inevitable if we wish to do something here. In which case lets go for something that more cleanly defines what we want to be doing: fully concurrent class-loading. Note: defineClassIfNotPresent is already implemented in the VM as find_or_define_class. It is only used if the AllowParallelDefineClass flag is set. This gives us an easy hook into existing VM mechanics. Proposal: Fully Concurrent ClassLoaders The proposal is that we expand on the notion of a parallel capable class loader and define a "fully concurrent parallel capable class loader" or fully concurrent loader, for short. A fully concurrent loader uses no synchronization in loadClass and the VM uses the "parallel define class" mechanism. For a fully concurrent loader getClassLoadingLock() can return null (or perhaps not - it doesn't matter as we won't use the result anyway). At present we have not made any changes to this method. All the parallel capable JDK classloaders become fully concurrent loaders. This doesn't require any code re-design as none of the mechanisms implemented rely on the per-name locking provided by the parallelLockMap. This seems to give us a path to remove all locking at the Java level during classloading, while retaining full compatibility with Java 7 parallel capable loaders. Fully concurrent loaders will still encounter the performance penalty associated with concurrent attempts to find and prepare a class's bytecode for definition by the VM. What this penalty is depends on the number of concurrent load attempts possible (a function of the number of threads and the application logic, and dependent on the number of processors), and the costs associated with finding and preparing the bytecodes. This obviously has to be measured across a range of applications. Preliminary webrevs: http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.hotspot/ http://cr.openjdk.java.net/~dholmes/concurrent-loaders/webrev.jdk/ Please direct all comments to the mailing list [email protected].

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  • YouTube: Promotional AgroSense Movie

    - by Geertjan
    Here's a cool YouTube promotional movie on AgroSense created by Ordina in the Netherlands. AgroSense is an open source Java system for the precision agriculture industry, which won the IT Environment Award in the Netherlands last week: If your understanding of Dutch limits your appreciation of the movie above, here's a rough translation, together with the names of the speakers in the movie: Precision agriculture, an innovative form of agriculture in which local variations in soil, crop, and atmosphere are taken into account, is the high-tech sustainable agriculture of tomorrow. The use of fertilizer, water, and energy can in this way be significantly reduced. "If, ten or twenty years from now, we are to continue having our agricultural industry in good shape, and in a continuing state of health, we'll need to register and work with data because if we want to enable crops to provide higher value, we'll need to create higher levels of transparency throughout the agriculture chain." Lenus Hamster, farmer in Nieuwolda Groningen "Industry is becoming increasingly data intensive. By combining pragmatic usefulness with innovative sustainability, AgroSense offers the Netherlands the possibility to continue being a leading player in the agrofood sector." Art Lighthart, Architect at Ordina AgroSense offers an open source solution in which all services for precision agriculture are brought together. In 2012, co-operation is being sought with organizations to make AgroSense available to around 10,000 Dutch farmers in the arable crop sector. By the way, the last sentence above implies the NetBeans Platform will be used by around 10,000 Dutch farmers.

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  • Not Drowning, Being Saved By a Dog

    - by Aaron Lazenby
    Really, there's no dog in this story. Just a week without travel to get some actual work done.I had plans to blog ambitiously from from Collaborate 10 (Wi-Fi was limited; iPad is still untested), but it's a much busier week than your agenda suggests.Scheduling sessions is one thing: you can count on those chunks of time being lost to the universe. It's the bumping into people in the hall and dropping in on an impromptu lunch that really knocks things out of whack.Good think too: I met with some great folks from

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  • Wrapping up an Exciting Mobile World Congress

    - by Jacob Lehrbaum
    Its been a busy week here in Barcelona, with noticeably more energy at the show than in 2010. This year, we decided to move the Java booth to the App Planet and really engage with the increasing number of developers that are attending the event. Our booth featured 10 demos and a series of nearly 25 workshops featuring a variety of topics ranging from information about Java Verified, to the use of web technologies with Java ME, to sessions hosted by Operators such as Orange and Telefonica (see image to the left).One of the more popular topics in our booth was the use of Java in the Smart Grid. In our booth we were showing off some of the work of the Hydra Consortium whose goal it is to leverage the emerging smart grid infrastructure to securely enable the delivery of personal health data (weight, blood pressure, etc) from the home to your doctor. If you'd like to learn more about this innovative project, you can watch a video that was filmed at the event featuring Charles Palmer of Onzo. If you'd like to learn more about Java in the Smart Grid, check out our on-demand webinar

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  • Twitter Storm VS. Google's MapReduce

    - by Edward J. Yoon
    IMO, the era of Information Retrieval is dead with the advent of SNS. And the question type is changed from "How many backlinks your site has?" to "How many people have clicked URL you've shared on SNS?". So many people who newbie in Big Data Analytics often asks me "How can I analyze stream data time-series pattern mining methods using Map/Reduce?", "How can I mining the valuable insights using Map/Reduce?", "blah~ blah~ using Map/Reduce?". The answer is No Map/Reduce.

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  • JSF 2.2, Interceptors 1.2, and JPA 2.1 Replay: Java EE 7 Launch Webinar Technical Breakouts on YouTube

    - by arungupta
    As stated previously (here, here, and here), the On-Demand Replay of Java EE 7 Launch Webinar is already available. You can watch the entire Strategy and Technical Keynote there, and all other Technical Breakout sessions as well. We are releasing the next set of Technical Breakout sessions on GlassFishVideos YouTube channel as well. In this series, we are releasing JSF 2.2, Interceptors 1.2, and JPA 2.1. Here's the JSF 2.2 session: Here's the Interceptors 1.1 session: Here's the JPA 2.1 session: Enjoy watching them over the next few days before we release the next set of videos! And don't forget to download Java EE 7 SDK and try numerous bundled samples.

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  • Recent uploaded slides for the Upgrade Talks last week

    - by Mike Dietrich
    Welcome 2011 :-) And here you'll find the newest talks Carol, Roy and Brian delivered last week in several cities (please find the also in the DOWNLOAD SLIDES section on the right side of this blog): Upgrade Methods and Upgrade Planning: Click here to Download and use the keyword: roy2011 +500 Slides Upgrade Workshop Presentation: Click here to Download and use the keyword (Schlüsselwort): upgrade112 Hope you had a nice weekend and wonderful weather, too, as we had yesterday south of Munich. Click pic for a higher resolution: Starnberg Lake - View towards the Alps

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  • Exploring TCP throughput with DTrace

    - by user12820842
    One key measure to use when assessing TCP throughput is assessing the amount of unacknowledged data in the pipe. This is sometimes termed the Bandwidth Delay Product (BDP) (note that BDP is often used more generally as the product of the link capacity and the end-to-end delay). In DTrace terms, the amount of unacknowledged data in bytes for the connection is the different between the next sequence number to send and the lowest unacknoweldged sequence number (tcps_snxt - tcps_suna). According to the theory, when the number of unacknowledged bytes for the connection is less than the receive window of the peer, the path bandwidth is the limiting factor for throughput. In other words, if we can fill the pipe without the peer TCP complaining (by virtue of its window size reaching 0), we are purely bandwidth-limited. If the peer's receive window is too small however, the sending TCP has to wait for acknowledgements before it can send more data. In this case the round-trip time (RTT) limits throughput. In such cases the effective throughput limit is the window size divided by the RTT, e.g. if the window size is 64K and the RTT is 0.5sec, the throughput is 128K/s. So a neat way to visually determine if the receive window of clients may be too small should be to compare the distribution of BDP values for the server versus the client's advertised receive window. If the BDP distribution overlaps the send window distribution such that it is to the right (or lower down in DTrace since quantizations are displayed vertically), it indicates that the amount of unacknowledged data regularly exceeds the client's receive window, so that it is possible that the sender may have more data to send but is blocked by a zero-window on the client side. In the following example, we compare the distribution of BDP values to the receive window advertised by the receiver (10.175.96.92) for a large file download via http. # dtrace -s tcp_tput.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 6 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 9 4096 | 14 8192 | 27 16384 | 67 32768 |@@ 1464 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 32396 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 16384 | 0 32768 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 17067 65536 | 0 Here we have a puzzle. We can see that the receiver's advertised window is in the 32768-65535 range, while the amount of unacknowledged data in the pipe is largely in the 65536-131071 range. What's going on here? Surely in a case like this we should see zero-window events, since the amount of data in the pipe regularly exceeds the window size of the receiver. We can see that we don't see any zero-window events since the SWND distribution displays no 0 values - it stays within the 32768-65535 range. The explanation is straightforward enough. TCP Window scaling is in operation for this connection - the Window Scale TCP option is used on connection setup to allow a connection to advertise (and have advertised to it) a window greater than 65536 bytes. In this case the scaling shift is 1, so this explains why the SWND values are clustered in the 32768-65535 range rather than the 65536-131071 range - the SWND value needs to be multiplied by two since the reciever is also scaling its window by a shift factor of 1. Here's the simple script that compares BDP and SWND distributions, fixed to take account of window scaling. #!/usr/sbin/dtrace -s #pragma D option quiet tcp:::send / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @bdp["BDP(bytes)", args[2]-ip_daddr, args[4]-tcp_sport] = quantize(args[3]-tcps_snxt - args[3]-tcps_suna); } tcp:::receive / (args[4]-tcp_flags & (TH_SYN|TH_RST|TH_FIN)) == 0 / { @swnd["SWND(bytes)", args[2]-ip_saddr, args[4]-tcp_dport] = quantize((args[4]-tcp_window)*(1 tcps_snd_ws)); } And here's the fixed output. # dtrace -s tcp_tput_scaled.d ^C BDP(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count -1 | 0 0 | 39 1 | 0 2 | 0 4 | 0 8 | 0 16 | 0 32 | 0 64 | 0 128 | 0 256 | 3 512 | 0 1024 | 0 2048 | 4 4096 | 9 8192 | 22 16384 | 37 32768 |@ 99 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 3858 131072 | 0 SWND(bytes) 10.175.96.92 80 value ------------- Distribution ------------- count 512 | 0 1024 | 1 2048 | 0 4096 | 2 8192 | 4 16384 | 7 32768 | 14 65536 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 1956 131072 | 0

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  • Introducing the Documentation Workflows

    - by Owen Allen
    The how-to documents  provide end to end examples of specific features, such as creating a new zone or discovering a new system. We are enhancing the individual how-tos with documents called Workflows. These workflows are each built around procedural flowcharts that show these larger and more complex tasks. The workflow indicates which how-tos or other workflows you should follow to complete a more complex process, and give you a flow for planning the execution of a process. Over the coming days I'll highlight each of these workflows, and talk about the tasks that each one guides you through.

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  • Sign-On für APEX Anwendungen mit Kerberos

    - by Carsten Czarski
    Endbenutzer von APEX-Anwendungen arbeiten fast immer von einem Windows-PC aus - und sehr oft sind sie in einer Windows-Domäne eingeloggt. Da liegt es doch nahe, diesen Login auch für die APEX-Anwendung zu verwenden und sich nicht erneut anmelden zu müssen. Leider unterstützt APEX ein solches Verfahren nicht out-of-the-box. Nimmt man jedoch einige Open-Source Komponenten hinzu, so lässt sich die Anforderung leicht umsetzen. Niels de Bruijn von der MT AG hat ein Dokument zusammengestellt, welches die Vorgehensweise beschreibt: Single Sign-On für APEX Anwendungen mit Kerberos - schauen Sie einfach mal rein.

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  • Current SPARC Architectures

    - by Darryl Gove
    Different generations of SPARC processors implement different architectures. The architecture that the compiler targets is controlled implicitly by the -xtarget flag and explicitly by the -arch flag. If an application targets a recent architecture, then the compiler gets to play with all the instructions that the new architecture provides. The downside is that the application won't work on older processors that don't have the new instructions. So for developer's there is a trade-off between performance and portability. The way we have solved this in the compiler is to assume a "generic" architecture, and we've made this the default behaviour of the compiler. The only flag that doesn't make this assumption is -fast which tells the compiler to assume that the build machine is also the deployment machine - so the compiler can use all the instructions that the build machine provides. The -xtarget=generic flag tells the compiler explicitly to use this generic model. We work hard on making generic code work well across all processors. So in most cases this is a very good choice. It is also of interest to know what processors support the various architectures. The following Venn diagram attempts to show this: A textual description is as follows: The T1 and T2 processors, in addition to most other SPARC processors that were shipped in the last 10+ years supported V9b, or sparcvis2. The SPARC64 processors from Fujitsu, used in the M-series machines, added support for the floating point multiply accumulate instruction in the sparcfmaf architecture. Support for this instruction also appeared in the T3 - this is called sparcvis3 Later SPARC64 processors added the integer multiply accumulate instruction, this architecture is sparcima. Finally the T4 includes support for both the integer and floating point multiply accumulate instructions in the sparc4 architecture. So the conclusion should be: Floating point multiply accumulate is supported in both the T-series and M-series machines, so it should be a relatively safe bet to start using it. The T4 is a very good machine to deploy to because it supports all the current instruction sets.

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  • The Sound of Two Toilets Flushing: Constructive Criticism for Virgin Atlantic Complaints Department

    - by Geertjan
    I recently had the experience of flying from London to Johannesburg and back with Virgin Atlantic. The good news was that it was the cheapest flight available and that the take off and landing were absolutely perfect. Hence I really have no reason to complain. Instead, I'd like to offer some constructive criticism which hopefully Richard Branson will find sometime while googling his name. Or maybe someone from the Virgin Atlantic Complaints Department will find it, whatever, just want to put this information out there. Arrangement of restroom facilities. Maybe next time you design an airplane, consider not putting your toilets at a right angle right next to your rows of seats. Being able to reach, without even needing to stretch your arm, from your seat to close, yet again, a toilet door that someone, someone obviously sitting very far from the toilets, carelessly forgot to close is not an indicator of quality interior design. Have you noticed how all other airplanes have their toilets in a cubicle separated from the rows of seats? On those airplanes, people sitting in the seats near the toilets are not constantly being woken up throughout the night whenever someone enters/exits the toilet, whenever the light in the toilet is suddenly switched on, and whenever one of the toilets flushes. Bonus points for Virgin Atlantic passengers in the seats adjoining the toilets is when multiple toilets are flushed simultaneously and multiple passengers enter/exit them at the same time, a bit like an unasked for low budget musical of suddenly illuminated grumpy people in crumpled clothes. What joy that brings at 3 AM is hard to describe. Seats with extra leg room. You know how other airplanes have the seats with the extra leg room? You know what those seats tend to have? Extra leg room. It's really interesting how Virgin Atlantic's seats with extra leg room actually have no extra leg room at all. It should have been a give away, the fact that these special seats are found in the same rows as the standard seats, rather than on the cusp of real glory which is where most airlines put their extra leg room seats, with the only actual difference being that they have a slightly different color. Had you called them "seats with a different color" (i.e., almost not quite green, rather than something vaguely hinting at blue), at least I'd have known what I was getting. Picture the joy at 3 AM, rudely awakened from nightmarish slumber, partly grateful to have been released from a grayish dream of faceless zombies resembling one or two of those in a recent toilet line, by multiple adjoining toilets flushing simultaneously, while you're sitting in a seat with extra leg room that has exactly as much leg room as the seats in neighboring rows. You then have a choice of things to be sincerely annoyed about. Food from the '80's. In the '80's, airplane food came in soggy containers and even breakfast, the most important meal of the day, was a sad heap of vaguely gray colors. The culinary highlight tended to be a squashed tomato, which must have been mashed to a pulp with a brick prior to being regurgitated by a small furry animal, and there was also always a piece of immensely horrid pumpkin, as well as a slice of spongy something you'd never seen before. Sausages and mash at 6 AM on an airplane was always a heavy lump of horribleness. Thankfully, all airlines throughout the world changed from this puke inducing strategy around 1987 sometime. Not Virgin Atlantic, of course. The fatty sausages and mash are still there, bringing you flashbacks to Duran Duran, which is what you were listening to (on your walkman) the last time you saw it in an airplane. Even the golden oldie "squashed tomato attached by slime to three wet peas" is on the menu. How wonderful to have all this in a cramped seat with a long row of early morning bleariness lined up for the toilets, right at your side, bumping into your elbow, groggily, one by one, one after another, more and more, fumble-open-door-silence-flush-fumble-open-door, and on and on, while you tentatively push your fork through a soggy pile of colorless mush, fighting the urge to throw up on the stinky socks of whatever nightmarish zombie is bumping into your elbow at the time. But, then again, the plane landed without a hitch, in fact, extremely smoothly, so I'm certainly not blaming the pilots.

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  • RPi and Java Embedded GPIO: Sensor Connections for Java Enabled Interface

    - by hinkmond
    Now we're ready to connect the hardware needed to make a static electricity sensor for the Raspberry Pi and use Java code to access it through a GPIO port. First, very carefully bend the NTE312 (or MPF-102) transistor "gate" pin (see the diagram on the back of the package or refer to the pin diagram on the Web). You can see it in the inset photo on the bottom left corner. I bent the leftmost pin of the NTE312 transistor as I held the flat part toward me. That is going to be your antenna. So, connect one of the jumper wires to the bent pin. I used the dark green jumper wire (looks almost black; coiled at the bottom) in the photo. Then push the other 2 pins of the transistor into your breadboard. Connect one of the pins to Pin # 1 (3.3V) on the GPIO header of your RPi. See the diagram if you need to glance back at it. In the photo, that's the orange jumper wire. And connect the final unconnected transistor pin to Pin # 22 (GPIO25) on the RPi header. That's the blue jumper wire in my photo. For reference, connect the LED anode (long pin on a common anode LED/short pin on a common cathode LED, check your LED pin diagram) to the same breadboard hole that is connecting to Pin # 22 (same row of holes where the blue wire is connected), and connect the other pin of the LED to GROUND (row of holes that connect to the black wire in the photo). Test by blowing up a balloon, rubbing it on your hair (or your co-worker's hair, if you are hair-challenged) to statically charge it, and bringing it near your antenna (green wire in the photo). The LED should light up when it's near and go off when you pull it away. If you need more static charge, find a co-worker with really long hair, or rub the balloon on a piece of silk (which is just as good but not as fun). Next blog post is where we do some Java coding to access this sensor on your RPi. Finally, back to software! Ha! Hinkmond

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  • Lessons From OpenId, Cardspace and Facebook Connect

    - by mark.wilcox
    (c) denise carbonell I think Johannes Ernst summarized pretty well what happened in a broad sense in regards to OpenId, Cardspace and Facebook Connect. However, I'm more interested in the lessons we can take away from this. First  - "Apple Lesson" - If user-centric identity is going to happen it's going to require not only technology but also a strong marketing campaign. I'm calling this the "Apple Lesson" because it's very similar to how Apple iPad saw success vs the tablet market. The iPad is not only a very good technology product but it was backed by a very good marketing plan. I know most people do not want to think about marketing here - but the fact is that nobody could really articulate why user-centric identity mattered in a way that the average person cared about. Second - "Facebook Lesson" - Facebook Connect solves a number of interesting problems that is easy for both consumer and service providers. For a consumer it's simple to log-in without any redirects. And while Facebook isn't perfect on privacy - no other major consumer-focused service on the Internet provides as much control about sharing identity information. From a developer perspective it is very easy to implement the SSO and fetch other identity information (if the user has given permission). This could only happen because a major company just decided to make a singular focus to make it happen. Third - "Developers Lesson" -  Facebook Social Graph API is by far the simplest API for accessing identity information which also is another reason why you're seeing such rapid growth in Facebook enabled Websites. By using a combination of URL and Javascript - the power a single HTML page now gives a developer writing Web applications is simply amazing. For example It doesn't get much simpler than this "http://api.facebook.com/mewilcox" for accessing identity. And while I can't yet share too much publicly about the specifics - the social graph API had a profound impact on me in designing our next generation APIs.  Posted via email from Virtual Identity Dialogue

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  • Migrating from GlassFish 2.x to 3.1.x

    - by alexismp
    With clustering now available in GlassFish since version 3.1 (our Spring 2011 release), a good number of folks have been looking at migrating their existing GlassFish 2.x-based clustered environments to a more recent version to take advantage of Java EE 6, our modular design, improved SSH-based provisioning and enhanced HA performance. The GlassFish documentation set is quite extensive and has a dedicated Upgrade Guide. It obviously lists a number of small changes such as file layout on disk (mostly due to modularity), some option changes (grizzly, shoal), the removal of node agents (using SSH instead), new JPA default provider name, etc... There is even a migration tool (glassfish/bin/asupgrade) to upgrade existing domains. But really the only thing you need to know is that each module in GlassFish 3 and beyond is responsible for doing its part of the upgrade job which means that the migration is as simple as copying a 2.x domain directory to the domains/ directory and starting the server with asadmin start-domain --upgrade. Binary-compatible products eligible for such upgrades include Sun Java System Application Server 9.1 Update 2 as well as version 2.1 and 2.1.1 of Sun GlassFish Enterprise Server.

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  • Tab Sweep - Java EE wins, Prime Faces JSF, NetBeans, Jelastic for GlassFish, BeanValidation, Ewok and more...

    - by alexismp
    Recent Tips and News on Java, Java EE 6, GlassFish & more : • PrimeFaces 3.2 Final Released (primefaces.org) • Java EE wins over Spring (Bill Burke) • Customizing Components in JSF 2.0 (Mr. Bool) • Key to the Java EE 6 Platform: NetBeans IDE 7.1.x (OTN) • How to use GlassFish’s Connection Pool in Jelastic (jelastic.com) • Bean Validation 1.1 early draft 1 is out - time for feedback (Emmanuel) • Code artifacts published for Bean Validation 1.1 early draft 1 (Emmanuel) • Aprendendo Java EE 6 com GlassFish 3 e NetBeans 7.1 (Marcello) • JavaEE6 and the Ewoks (Murat)

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  • What is MDS ?

    - by harsh.singla
    MDS is Metadata store used to store shared artifacts in AIA 11gR1. The shared artifacts are the artifacts which are used by multiple composites. These are like xsds, wsdls, xsls etc. Instead of hosting on http location, we use MDS to store these artifacts. We use 'oramds' protocol in all the composites instead of 'http'.

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  • E-books make smart kids using Java ME mobile phones

    - by hinkmond
    Worldreader has been distributing e-books on Kindle devices to children in sub-Saharan Africa to teach the students how to read. But now, Worldreader has also created a Java ME app that helps even more students in developing countries to have access to free books. See: Reaching more students w/Java ME Here's a quote: In many African countries, 80 percent of the population owns a cell phone. Up to now, Worldreader has focused on distributing Kindles to classrooms (the organization’s founder is former Amazon exec, but by making e-books available via cell phones the organization can reach a much wider group of readers. Using technology to teach kids how to read in developing nations is a good way to use mobile devices like Java ME feature phones--a lot better than trying to slingshot cartoon angry birds at green pigs on those other platforms, doncha think? Hinkmond

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  • Search in Projects API

    - by Geertjan
    Today I got some help from Jaroslav Havlin, the creator of the new "Search in Projects API". Below are the steps to create a search provider that finds recently modified files, via a new tab in the "Find in Projects" dialog: Here's how to get to the above result. Create a new NetBeans module project named "RecentlyModifiedFilesSearch". Then set dependencies on these libraries: Search in Projects API Lookup API Utilities API Dialogs API Datasystems API File System API Nodes API Create and register an implementation of "SearchProvider". This class tells the application the name of the provider and how it can be used. It should be registered via the @ServiceProvider annotation.Methods to implement: Method createPresenter creates a new object that is added to the "Find in Projects" dialog when it is opened. Method isReplaceSupported should return true if this provider support replacing, not only searching. If you want to disable the search provider (e.g., there aren't required external tools available in the OS), return false from isEnabled. Method getTitle returns a string that will be shown in the tab in the "Find in Projects" dialog. It can be localizable. Example file "org.netbeans.example.search.ExampleSearchProvider": package org.netbeans.example.search; import org.netbeans.spi.search.provider.SearchProvider; import org.netbeans.spi.search.provider.SearchProvider.Presenter; import org.openide.util.lookup.ServiceProvider; @ServiceProvider(service = SearchProvider.class) public class ExampleSearchProvider extends SearchProvider { @Override public Presenter createPresenter(boolean replaceMode) { return new ExampleSearchPresenter(this); } @Override public boolean isReplaceSupported() { return false; } @Override public boolean isEnabled() { return true; } @Override public String getTitle() { return "Recent Files Search"; } } Next, we need to create a SearchProvider.Presenter. This is an object that is passed to the "Find in Projects" dialog and contains a visual component to show in the dialog, together with some methods to interact with it.Methods to implement: Method getForm returns a JComponent that should contain controls for various search criteria. In the example below, we have controls for a file name pattern, search scope, and the age of files. Method isUsable is called by the dialog to check whether the Find button should be enabled or not. You can use NotificationLineSupport passed as its argument to set a display error, warning, or info message. Method composeSearch is used to apply the settings and prepare a search task. It returns a SearchComposition object, as shown below. Please note that the example uses ComponentUtils.adjustComboForFileName (and similar methods), that modifies a JComboBox component to act as a combo box for selection of file name pattern. These methods were designed to make working with components created in a GUI Builder comfortable. Remember to call fireChange whenever the value of any criteria changes. Example file "org.netbeans.example.search.ExampleSearchPresenter": package org.netbeans.example.search; import java.awt.FlowLayout; import javax.swing.BoxLayout; import javax.swing.JComboBox; import javax.swing.JComponent; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JSlider; import javax.swing.event.ChangeEvent; import javax.swing.event.ChangeListener; import org.netbeans.api.search.SearchScopeOptions; import org.netbeans.api.search.ui.ComponentUtils; import org.netbeans.api.search.ui.FileNameController; import org.netbeans.api.search.ui.ScopeController; import org.netbeans.api.search.ui.ScopeOptionsController; import org.netbeans.spi.search.provider.SearchComposition; import org.netbeans.spi.search.provider.SearchProvider; import org.openide.NotificationLineSupport; import org.openide.util.HelpCtx; public class ExampleSearchPresenter extends SearchProvider.Presenter { private JPanel panel = null; ScopeOptionsController scopeSettingsPanel; FileNameController fileNameComboBox; ScopeController scopeComboBox; ChangeListener changeListener; JSlider slider; public ExampleSearchPresenter(SearchProvider searchProvider) { super(searchProvider, false); } /** * Get UI component that can be added to the search dialog. */ @Override public synchronized JComponent getForm() { if (panel == null) { panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS)); JPanel row1 = new JPanel(new FlowLayout(FlowLayout.LEADING)); JPanel row2 = new JPanel(new FlowLayout(FlowLayout.LEADING)); JPanel row3 = new JPanel(new FlowLayout(FlowLayout.LEADING)); row1.add(new JLabel("Age in hours: ")); slider = new JSlider(1, 72); row1.add(slider); final JLabel hoursLabel = new JLabel(String.valueOf(slider.getValue())); row1.add(hoursLabel); row2.add(new JLabel("File name: ")); fileNameComboBox = ComponentUtils.adjustComboForFileName(new JComboBox()); row2.add(fileNameComboBox.getComponent()); scopeSettingsPanel = ComponentUtils.adjustPanelForOptions(new JPanel(), false, fileNameComboBox); row3.add(new JLabel("Scope: ")); scopeComboBox = ComponentUtils.adjustComboForScope(new JComboBox(), null); row3.add(scopeComboBox.getComponent()); panel.add(row1); panel.add(row3); panel.add(row2); panel.add(scopeSettingsPanel.getComponent()); initChangeListener(); slider.addChangeListener(new ChangeListener() { @Override public void stateChanged(ChangeEvent e) { hoursLabel.setText(String.valueOf(slider.getValue())); } }); } return panel; } private void initChangeListener() { this.changeListener = new ChangeListener() { @Override public void stateChanged(ChangeEvent e) { fireChange(); } }; fileNameComboBox.addChangeListener(changeListener); scopeSettingsPanel.addChangeListener(changeListener); slider.addChangeListener(changeListener); } @Override public HelpCtx getHelpCtx() { return null; // Some help should be provided, omitted for simplicity. } /** * Create search composition for criteria specified in the form. */ @Override public SearchComposition<?> composeSearch() { SearchScopeOptions sso = scopeSettingsPanel.getSearchScopeOptions(); return new ExampleSearchComposition(sso, scopeComboBox.getSearchInfo(), slider.getValue(), this); } /** * Here we return always true, but could return false e.g. if file name * pattern is empty. */ @Override public boolean isUsable(NotificationLineSupport notifySupport) { return true; } } The last part of our search provider is the implementation of SearchComposition. This is a composition of various search parameters, the actual search algorithm, and the displayer that presents the results.Methods to implement: The most important method here is start, which performs the actual search. In this case, SearchInfo and SearchScopeOptions objects are used for traversing. These objects were provided by controllers of GUI components (in the presenter). When something interesting is found, it should be displayed (with SearchResultsDisplayer.addMatchingObject). Method getSearchResultsDisplayer should return the displayer associated with this composition. The displayer can be created by subclassing SearchResultsDisplayer class or simply by using the SearchResultsDisplayer.createDefault. Then you only need a helper object that can create nodes for found objects. Example file "org.netbeans.example.search.ExampleSearchComposition": package org.netbeans.example.search; public class ExampleSearchComposition extends SearchComposition<DataObject> { SearchScopeOptions searchScopeOptions; SearchInfo searchInfo; int oldInHours; SearchResultsDisplayer<DataObject> resultsDisplayer; private final Presenter presenter; AtomicBoolean terminated = new AtomicBoolean(false); public ExampleSearchComposition(SearchScopeOptions searchScopeOptions, SearchInfo searchInfo, int oldInHours, Presenter presenter) { this.searchScopeOptions = searchScopeOptions; this.searchInfo = searchInfo; this.oldInHours = oldInHours; this.presenter = presenter; } @Override public void start(SearchListener listener) { for (FileObject fo : searchInfo.getFilesToSearch( searchScopeOptions, listener, terminated)) { if (ageInHours(fo) < oldInHours) { try { DataObject dob = DataObject.find(fo); getSearchResultsDisplayer().addMatchingObject(dob); } catch (DataObjectNotFoundException ex) { listener.fileContentMatchingError(fo.getPath(), ex); } } } } @Override public void terminate() { terminated.set(true); } @Override public boolean isTerminated() { return terminated.get(); } /** * Use default displayer to show search results. */ @Override public synchronized SearchResultsDisplayer<DataObject> getSearchResultsDisplayer() { if (resultsDisplayer == null) { resultsDisplayer = createResultsDisplayer(); } return resultsDisplayer; } private SearchResultsDisplayer<DataObject> createResultsDisplayer() { /** * Object to transform matching objects to nodes. */ SearchResultsDisplayer.NodeDisplayer<DataObject> nd = new SearchResultsDisplayer.NodeDisplayer<DataObject>() { @Override public org.openide.nodes.Node matchToNode( final DataObject match) { return new FilterNode(match.getNodeDelegate()) { @Override public String getDisplayName() { return super.getDisplayName() + " (" + ageInMinutes(match.getPrimaryFile()) + " minutes old)"; } }; } }; return SearchResultsDisplayer.createDefault(nd, this, presenter, "less than " + oldInHours + " hours old"); } private static long ageInMinutes(FileObject fo) { long fileDate = fo.lastModified().getTime(); long now = System.currentTimeMillis(); return (now - fileDate) / 60000; } private static long ageInHours(FileObject fo) { return ageInMinutes(fo) / 60; } } Run the module, select a node in the Projects window, press Ctrl-F, and you'll see the "Find in Projects" dialog has two tabs, the second is the one you provided above:

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  • Annotation Processing Virtual Mini-Track at JavaOne 2012

    - by darcy
    Putting together the list of JavaOne talks I'm interested in attending, I noticed there is a virtual mini-track on annotation processing and related technology this year, with a combination of bofs, sessions, and a hands-on-lab: Monday Multidevice Content Display and a Smart Use of Annotation Processing, Dimitri BAELI and Gilles Di Guglielmo Tuesday Advanced Annotation Processing with JSR 269, Jaroslav Tulach Build Your Own Type System for Fun and Profit, Werner Dietl and Michael Ernst Wednesday Annotations and Annotation Processing: What’s New in JDK 8?, Joel Borggrén-Franck Thursday Hack into Your Compiler!, Jaroslav Tulach Writing Annotation Processors to Aid Your Development Process, Ian Robertson As the lead engineer on bot apt (rest in peace) in JDK 5 and JSR 269 in JDK 6, I'd be heartened to see greater adoption and use of annotation processing by Java developers.

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  • Mobile Shopping Alerts

    - by David Dorf
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} It’s been popular to offer coupons when people check-in to a store, because you’re catching them at the best possible time – they’re presumably in a shopping state-of-mind, and they’re at your store.  But wouldn’t it be even better to catch the people walking by your store and entice them to visit?  That’s the concept of geo-fences.  When people enter a geographic zone, they are sent a relevant text message alerting them about something nearby. I wrote about Placecast doing this for The North Face, noting that the messages were a unique combination of both offers and useful information about outdoor activities. After creating a program with European carrier O2, Placecast recently entered into an agreement to provide similar services to AT&T customers.  The ShopAlerts program allows AT&T customers in Chicago, Los Angeles, New York City, and San Francisco opt-in to receive these messages.  The program will be expanded nationwide as early as this summer. It’s a much better model for customers (and Placecast) to sign-up once with the carrier instead of each individual retailer, but I hope the messages aren’t restricted to advertising.  I really the like the idea of providing other information, such as nearby special events, races, and perhaps even things to avoid like construction.

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  • Netcat I/O enhancements

    - by user13277689
    When Netcat integrated into OpenSolaris it was already clear that there will be couple of enhancements needed. The biggest set of the changes made after Solaris 11 Express was released brings various I/O enhancements to netcat shipped with Solaris 11. Also, since Solaris 11, the netcat package is installed by default in all distribution forms (live CD, text install, ...). Now, let's take a look at the new functionality: /usr/bin/netcat alternative program name (symlink) -b bufsize I/O buffer size -E use exclusive bind for the listening socket -e program program to execute -F no network close upon EOF on stdin -i timeout extension of timeout specification -L timeout linger on close timeout -l -p port addr previously not allowed usage -m byte_count Quit after receiving byte_count bytes -N file pattern for UDP scanning -I bufsize size of input socket buffer -O bufsize size of output socket buffer -R redir_spec port redirection addr/port[/{tcp,udp}] syntax of redir_spec -Z bypass zone boundaries -q timeout timeout after EOF on stdin Obviously, the Swiss army knife of networking tools just got a bit thicker. While by themselves the options are pretty self explanatory, their combination together with other options, context of use or boundary values of option arguments make it possible to construct small but powerful tools. For example: the port redirector allows to convert TCP stream to UDP datagrams. the buffer size specification makes it possible to send one byte TCP segments or to produce IP fragments easily. the socket linger option can be used to produce TCP RST segments by setting the timeout to 0 execute option makes it possible to simulate TCP/UDP servers or clients with shell/python/Perl/whatever script etc. If you find some other helpful ways use please share via comments. Manual page nc(1) contains more details, along with examples on how to use some of these new options.

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