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How to Configure HTTPS SSL in Tomcat 6 and 7 Java Web Server
Setting SSL (Secure Socket Layer) in Tomcat is often a requirement, especially while developing secure web application, which requires access over https protocol. Since Tomcat web server doesn't provide SSL settings by default, you need to know how to configure SSL in tomcat, and even worse it varies between different tomcat versions. for Example SSL setup which works on tomcat 6, doesn't work as it is in tomcat 7. In this article we will see, how to configure tomcat for https in both tomcat 6 and 7. For those programmers who are not very familiar with SSL and https here is a quick overview of SSL, certificates and https, and I suggest reading that article to get better understanding of How SSL works and How websites are accessed security over internet.
Oracle 10g Pagination Query SQL Example for Java Programmer
Kamis, 27 Februari 2014
Many time we need SQL query which return data page by page i.e. 30 or 40 records at a time, which can be specified as page size. In fact Database pagination is common requirement of Java web developers, especially dealing with largest data sets. In this article we will see how to query Oracle 10g database for pagination or how to retrieve data using paging from Oracle. Many Java programmer also use display tag for paging in JSP which supports both internal and external paging. In case of internal paging all data is loaded in to memory in one shot and display tag handles pagination based upon page size but it only suitable for small data where you can afford those many objects in memory. If you have hundreds of row to display than its best to use external pagination by asking databaseto do pagination. In pagination, ordering is another important aspect which can not be missed. It’s virtually impossible to sort large collection in Java using Comparator or Comparablebecause of limited memory available to Java program, sorting data in database using ORDER BY clause itself is good solution while doing paging in web application.
RIM Introduce the BlackBerry 7
Rabu, 26 Februari 2014
Research In Motion (RIM) announced plans to launch five new BlackBerry smartphones based on operating system (OS) Blackberry 7. Together with partner operators and distributors around the world, presenting two models of RIMs BlackBerry Bold and BlackBerry Torch three models are equipped the latest BlackBerry OS 7.
The presence of various types of new handsets this will be the biggest launch ever undertaken globally RIM along with 225 operator and distributor partners who have run and completed the 500 programs that have been certified for five new handsets.
"This is a global launch of the BlackBerry largest in history," said Mike Lazaridis, President and CEO of Research In Motion.
"Blackberry solution offers a best mobile experience, like users and we are confident they will be impressed with the fast performance, better browsing system and is rich in multimedia where all this is present in the BlackBerry Bold and BlackBerry recent Torch," said Lazaridis.
With the presence of the latest generation of hardware and software from RIM, Blackberry smartphones that use the fifth Blackberry OS 7 offers a variety of design models that can be selected to produce the communications, multimedia and the highest productivity for its users.
BlackBerry Bold 9900 and 9930 is the thinnest smartphone RIM has ever released, where each device has a great keyboard and touch display is brilliant. TorchTM BlackBerry 9810 smartphone is designed based on the popularity of the BlackBerry TorchTM 9800 combined with a large touch display with slide-out keyboard that will allow its users.
TorchTM BlackBerry 9850 and 9860 as a whole will introduce a new design with a touch display featuring touch the largest display ever on a BlackBerry.
Inter Thread Communication in Java using Wait Notify Example
Selasa, 25 Februari 2014
Wait and notify methods in Java are used for inter-thread communication i.e. if one thread wants to tell something to another thread, it uses notify() and notifyAll() method of java.lang.Object. Classical example of wait and notify method is Producer Consumer design pattern, where One thread produce and put something on shared bucket, and then tell other thread that there is an item for your interest in shared object, consumer thread than pick than item and do his job, without wait() and notify(), consumer thread needs to be busy checking, even if there is no change in state of shared object. This brings an interesting point on using wait and notify mechanism, a call to notify() happens, when thread changed state of shared object i.e. in this case producer change bucket from empty to not empty, and consumer change state from non empty to empty. Also wait and notify method must be called from synchronized context, wondering why, read this link for some reasons which makes sense. Another important thing to keep in mind while calling them is, using loop to check conditions instead of if block. This is really tricky for beginners, which often don't understand difference and wonders why wait and notify get called form loops. Joshua Bloch has a very informative item on his book Effective Java, I strongly suggest reading that. In short, a waiting thread may woke up, without any change in it's waiting condition due to spurious wake up. For example, if a consumer thread, which is waiting because shared queue is empty, gets wake up due to a false alarm and try to get something from queue without further checking whether queue is empty or not than unexpected result is possible. Here is standard idiom for calling wait, notify and notifyAll methods in Java :
How to call wait method in Java :
Read more »How to call wait method in Java :
Difference between ArrayList and Vector in Java
Senin, 24 Februari 2014
ArrayList and Vector are two of most used class on java collection package and difference between Vector and ArrayList is one of the most frequently asked java interview question on first round or phone interview. Though it’s quite a simple question in my opinion but knowledge of when to use Vector over ArrayList or does matter if you are working on a project. In this article we will some point based difference between Vector and ArrayList in Java and trying to understand the concept behind those differences. Ultimate goal is to familiarize yourself with distinguish property of ArrayList and Vector. By the way Java 5 adds another implementation of List interface which is similar to Vector and ArrayList but provides better concurrency access than Vector, its called CopyOnWriteArrayList. By the way this is the third article on discussing about Collection interview question, Difference between LinkedList and ArrayList and List vs Set are other popular interview questions based upon collection framework in Java.
Read more »Computer Security Computer Threats Threats That Can Cost
Minggu, 23 Februari 2014
Computer security threats have price most of the people around $2000 to shop for a brand new laptop computer. once the threats ar infecting their laptop, they cant do something and need to purchase a brand new laptop. have you ever ever questioning why your laptop is running slow? Or why your memory usage is usually 100%? Or ar you obtaining an equivalent pop-up on every occasion you open your net browser? These ar caused by the nasty threats that lurk in your laptop.
Therefore, laptop security is vital to any or all web users. These threats bring nothing however hassle and it will additionally price you your personal and confidential data. There are ways to get rid of the threats that did not cost you near a price of a laptop. But, before you find out how to get rid of the threats, 1st you need to grasp what the threats ar.
In this article, ill justify 10 must-know threats for any laptop and web users.
1. web Worms
Internet worms ar programs which will have an effect on another laptop on an equivalent network and it works otherwise from virus. It does not got to attach itself to a different programs to be harmful and might produce a certain copy of itself. Worms unfold via network and consume information measure. have you ever ever questioning why your network affiliation becomes thus slow? itd be attributable to the worms. Worms will have several malicious effects like inflicting a server to crash, make a users files unusable, or making a backdoor on target laptop.
2. Rootkit
Rootkit will hide it presence in a laptop and will avoid detection whereas running its utilities. It can create a backdoor heading in the right direction computer and permit hacker to send spam emails or use the target computer to perform denial-of-service attack on servers. police investigation its troublesome because it will conceal its presence in an exceedingly laptop. a method to find its by running virus scanner whereas it is not running. during this case, running the antivirus before the system boots the magnetic disc.
3. Zombies
When a deadly disease or trojan has infected a users computer, itll open a backdoor to permit hackers use the infected computer for malicious purpose without the owner knowledge. This infected laptop is named the zombie. what is more, the hacker will sell the target laptop access to others and others will use if for their own purpose. If a sender has gained Associate in Nursing access to the target laptop, itll use it to send spam.
4. Browser Hijacker
A browser hijacker can change your browser home page or search pages in your browser. In worse cases, it will disable your web choice thus you cant amendment the house page to the default home page. what is more, the browser hijacker will edit the written record thus it will run on every occasion you restart the Windows.
5. Email Virus
Email virus will distribute itself victimization email as Associate in Nursing attachment. When you open the attachment, it will launch the virus and the virus will use the target computer to send the same email with the same attachment to other computer. It may also notice files containing email addresses within the target laptop and send an equivalent email to the e-mail addresses that it found. Sometimes, it will launch itself once the user views the e-mail albeit the user did not launch the attachment.
6. Mousetrapping
Was there a time once you cannot leave a website? this is often called mousetrapping. the web site can use a script preventing the web user from going the web site. Sometimes, itll open a brand new browser and can display an equivalent website. so as to stop this from happening, you would like to disable java script that the script now not operating.
7. Phishing
This is another threat that we have a tendency to Janus-faced on-line. Phishing may be a term comes from fishing as a result of the phisher can attempt to acquire your personal data victimization bastard emails or bastard websites. If the phishers wish to get your PayPal username and watchword, theyre going to create a web site thats the precise copy of PayPal and can email you asking you to enter your username and password using the link provided. The link they provided within the email wont head to PayPal, instead, itll head to the phishing web site and if you enter your username and watchword, they can use it to get your cash out of PayPal.
8. Spam
Spam is that the junk emails or bulk emails send by the spammer to numerous recipients aimed to advertise something, scam, or causing virus. Spam will disguise itself as a private email to bypass the spam blocker. Some spams do no damage however it is a waste of your time deleting it and it is also annoying.
9. Spyware
A spyware is computer code utilized by hackers and advertisers to achieve data concerning you. When visiting certain websites, you are asked to put in this kind of computer code or updates that you simply want and also the updates that you simply put in are literally spyware. Spyware may also install itself in your laptop and it consumes memory usage and can block your laptop.
10. Adware
Software that displays advertising in your laptop is adware and a few of it put in itself in your laptop while not you knowing. However, not all adware ar unhealthy. a number of its accustomed advertise one thing to fund the corporate. This kind of adware can raise and tell you that they can install computer code that can show connected advertising in your laptop. But, adware may be a drawback if its too troublesome to uninstall, or it put in itself while not you knowing, or it hijack your application and block your laptop. this kind of adware must be removed.
https://www.allinonetech.net/computer-security.html
Therefore, laptop security is vital to any or all web users. These threats bring nothing however hassle and it will additionally price you your personal and confidential data. There are ways to get rid of the threats that did not cost you near a price of a laptop. But, before you find out how to get rid of the threats, 1st you need to grasp what the threats ar.
In this article, ill justify 10 must-know threats for any laptop and web users.
1. web Worms
Internet worms ar programs which will have an effect on another laptop on an equivalent network and it works otherwise from virus. It does not got to attach itself to a different programs to be harmful and might produce a certain copy of itself. Worms unfold via network and consume information measure. have you ever ever questioning why your network affiliation becomes thus slow? itd be attributable to the worms. Worms will have several malicious effects like inflicting a server to crash, make a users files unusable, or making a backdoor on target laptop.
2. Rootkit
Rootkit will hide it presence in a laptop and will avoid detection whereas running its utilities. It can create a backdoor heading in the right direction computer and permit hacker to send spam emails or use the target computer to perform denial-of-service attack on servers. police investigation its troublesome because it will conceal its presence in an exceedingly laptop. a method to find its by running virus scanner whereas it is not running. during this case, running the antivirus before the system boots the magnetic disc.
3. Zombies
When a deadly disease or trojan has infected a users computer, itll open a backdoor to permit hackers use the infected computer for malicious purpose without the owner knowledge. This infected laptop is named the zombie. what is more, the hacker will sell the target laptop access to others and others will use if for their own purpose. If a sender has gained Associate in Nursing access to the target laptop, itll use it to send spam.
4. Browser Hijacker
A browser hijacker can change your browser home page or search pages in your browser. In worse cases, it will disable your web choice thus you cant amendment the house page to the default home page. what is more, the browser hijacker will edit the written record thus it will run on every occasion you restart the Windows.
5. Email Virus
Email virus will distribute itself victimization email as Associate in Nursing attachment. When you open the attachment, it will launch the virus and the virus will use the target computer to send the same email with the same attachment to other computer. It may also notice files containing email addresses within the target laptop and send an equivalent email to the e-mail addresses that it found. Sometimes, it will launch itself once the user views the e-mail albeit the user did not launch the attachment.
6. Mousetrapping
Was there a time once you cannot leave a website? this is often called mousetrapping. the web site can use a script preventing the web user from going the web site. Sometimes, itll open a brand new browser and can display an equivalent website. so as to stop this from happening, you would like to disable java script that the script now not operating.
7. Phishing
This is another threat that we have a tendency to Janus-faced on-line. Phishing may be a term comes from fishing as a result of the phisher can attempt to acquire your personal data victimization bastard emails or bastard websites. If the phishers wish to get your PayPal username and watchword, theyre going to create a web site thats the precise copy of PayPal and can email you asking you to enter your username and password using the link provided. The link they provided within the email wont head to PayPal, instead, itll head to the phishing web site and if you enter your username and watchword, they can use it to get your cash out of PayPal.
8. Spam
Spam is that the junk emails or bulk emails send by the spammer to numerous recipients aimed to advertise something, scam, or causing virus. Spam will disguise itself as a private email to bypass the spam blocker. Some spams do no damage however it is a waste of your time deleting it and it is also annoying.
9. Spyware
A spyware is computer code utilized by hackers and advertisers to achieve data concerning you. When visiting certain websites, you are asked to put in this kind of computer code or updates that you simply want and also the updates that you simply put in are literally spyware. Spyware may also install itself in your laptop and it consumes memory usage and can block your laptop.
10. Adware
Software that displays advertising in your laptop is adware and a few of it put in itself in your laptop while not you knowing. However, not all adware ar unhealthy. a number of its accustomed advertise one thing to fund the corporate. This kind of adware can raise and tell you that they can install computer code that can show connected advertising in your laptop. But, adware may be a drawback if its too troublesome to uninstall, or it put in itself while not you knowing, or it hijack your application and block your laptop. this kind of adware must be removed.
https://www.allinonetech.net/computer-security.html
The pre Java Interview online written test questions that I hate
| Some online assessment sites basically try to test your memorizing capabilities with API based questions listed below. Also, about 30% - 50% of the questions are on API that you rarely use or obsolete. When you have the API documentation, why remember the API. Here are a few such questions I came across recently. If you want to ask such questions, then allow people to refer to the online API documentation. These tests are only going to filter out quality candidates. |
Q. Which of the following are valid JavaMail message types?
a) Message.RecipientType.CC
b) MessageRecipientType.CC
c) Message.RecipientType.CCList
d) Message.RecipientType.BCC
e) MessageRecipientType.BCC
A. a and d
Q. Which of the following are JNDI event listeners?
a) NamespaceChangeListener
b) ObjectListener
c) ObjectChangeListener
d) UnsolicitedNotificationListener
e) ObjectNotFoundListenr
A. a, c, and d.
Q. Which of the following statements are correct, based on the following code snippet for uploading a file?
<form action="upload" enctype="multipart/form-data">
<input type="text" name="description" />
<input type="file" name="file" />
<input type="submit" />
</form>
a) The enctype must be "text/form-data"
b) The method attribute is missing in the "form" element and it should be of type "GET"
c) The method attribute is missing in the "form" element and it should be of type "POST"
d) The "input" element must have the attribute "value"
e) The above syntax is correct
A. c.
The correct format is:
<form action="upload" method="post" enctype="multipart/form-data">
<input type="text" name="description" />
<input type="file" name="file" />
<input type="submit" />
</form>
Q. Which of the following objects are NOT part of the JavaBean Activation Framework (JAF)?
a) DataSource
b) DataFileHandler
c) DataHandler
d) DataContentHandler
e) FileDateHandler
f) FileTypeMap
A. b and e. All the others are part of JAF.
Q. Which of the following statements are INCORRECT?
a) HttpServletRequest.getRemoteUser( ) return null;
b) HttpServletRequest.isUserInRole(java.lang.String role) throws SecurityException ;
c) HttpServletRequest.getRemoteUser( ) return false;
d) HttpServletRequest.isUserInRole(java.lang.String role) return false;
e) HttpServletRequest.getUserPrincipal( ) throws SecurityException
f) HttpServletRequest.getUserPrincipal( ) return null;
A. b, c, and e are INCORRECT.
Q. Which of the following elements would you see in a SOAP payload with attachments?
a) <soap:header>
b) <soap:footer>
c) <soap:body>
d) <soap:content>
e) <soap:attachment>
A. a and c.
Q. Which of the following can be used in place of "****" in the code snippet shown below?
if(request.getParameter("location").equals("nextPage") {
*****
}
a) request.sendRedirect("url");
b) response.sendRedirect("url");
c) request.redirect("url");
d) response.redirect("url");
e) response.send("url")
A.b
Q. Which of the following are valid JDBC result set types?
a) TYPE_FORWARD_ONLY
b) TYPE_BACKWARD_ONLY
c) TYPE_SCROLL_INSENSITIVE
d) TYPE_SCROLL_SENSITIVE
e) TYPE_SCROLL_REVERSE
A. a, c, and d.
Q. Which of the following are valid JSP life cycle methods?
a) jspService( )
b)_jspService( )
c) jspInit( )
d) jspDestroy( )
e) _jspInit()
A. a, c, and d.
Q. Which of the following are CORRECT about JCA?
a) JCA is a standard architecture for integrating heterogeneous EIS systems not written in Java
b) JCA is a standard architecture for integrating other JEE systems
c) JCA can be used to integrate with mainframe systems
d) JCA can be used to integrate with ERP systems
e) JCA can be used to integrate with Database systems
f) The underlying EIS systems are integrated using pluggable resource adapters
A. a, c, d, e and f.
Q. Which of the following are INCORRECT about JAAS?
a) JAAS bring in location based authentication and authorization to JEE.
b) JAAS is designed to bring subject based authentication and authorization to JEE
c) JAAS is modeled after the Pluggable Authentication Module (PAM)-a popular API for defining authentication modules in a portable and extensible manner
d) JAAS can be used across managed resources such as servlet/JSP, EJB, or MBeans and over a variety of connection protocols such as HTTP, RMI/IIOP, or JMX/RMI.
e) JAAS was fully integrated into the core Java security architecture
A. a.
The last 2 questions are not bad, but for most of the other questions, the answers can be found by jumping on a search engine for 5 to 15 minutes. It is not really testing your understanding of the core concepts or hands-on experience.
Is it just me, or do you agree with me? Please post the Java Interview Questions that you hate.
iTunes 9 Released new version of Fetch Art coming soon
Sabtu, 22 Februari 2014
Today Apple released iTunes 9. I am currently testing a new version of Fetch Art and should know about compatibility with iTunes 9 and have a new version with some bug fixes available in about a week.
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How to fix java io NotSerializableException org apache log4j Logger Error in Java
Jumat, 21 Februari 2014
java.io.NotSerializableException: org.apache.log4j.Logger error says that instance of org.apache.lo4j.Logger is not Serializable. This error comes when we use log4j for logging in Java and create Logger in a Serializable class e.g. any domain class or POJO which we want to store in HttpSession or want to serialize it. As we know from 10 Java Serialization interview question that, if you have a non serializable class as member in a Serializable class, it will throw java.io.NotSerializableException Exception.
Look at the below code :
public class Customer implements Serializable{
private Logger logger = Logger.getLogger(Customer.class)
......
}
If instance of Customer will be stored in HttpSession or Serialized externally it will throw "java.io.NotSerializableException: org.apache.log4j.Logger" because here logger instance is neither staticor transientand it doesnt implement Serializable or Externalzable interface.
How to solve java.io.NotSerializableException: org.apache.log4j.Logger
Solving java.io.NotSerializableException: org.apache.log4j.Logger is simple, you have to prevent logger instance from default serializabtion process, either make it transient or static. Making it static final is preferred option due to many reason because if you make it transient than after deserialization logger instance will be null and any logger.debug() call will result in NullPointerException in Java because neither constructornot instance initializer block is called during deserialization. By making it static and final you ensure that its thread-safeand all instance of Customer class can share same logger instance, By the way this error is also one of the reason Why Logger should be declared static and finalin Java program. Just make following code change to fix java.io.NotSerializableException: org.apache.log4j.Logger in Java.public class Customer implements Serializable{
private static final Logger logger = Logger.getLogger(Customer.class)
......
}
Thats all on how to fix java.io.NotSerializableException: org.apache.log4j.Logger in Java. We have seen what cause java.io.NotSerializableException: org.apache.log4j.Logger, its because Logger class is not Serializable but we also learned that there is no point serializing Logger instance and better to make Logger static and final.
Other Serialization and troubleshooting articles from Javarevisited Blog
Recognize the sound of “BEEP on your PC
Kamis, 20 Februari 2014
Maybe you often encounter or maybe hear Beep on bios or PC. Actually the sound is a reply message conveyed by the bios / PC to indicate a hardware error on your PC.
Here I will try to give signs or information about the BEEP sound. But, please ensure the type of your PC bios.
AMI BIOS
Beeps 1x = > RAM is faulty or not installed properly.
Beep 6x = > usually indicates a defective keyboard, or not installed properly
Beep 8x = > Graphics card is damaged or improperly installed in the slot.
Beep 11x = > Checksum - Error. Check the CMOS battery on the motherboard.
Award BIOS
Long continuous beeps 1x = > RAM is damaged, or improperly installed.
Long beep 1x, 1x short = > There is a problem with the RAM or motherboard
Long beep 1x, 2x short = > Graphics card is damaged or not installed properly
1x long beep, short 3x = > Keyboard damaged or improperly installed
1x long beep, short 9x = > There is a problem with the Bios / Bios damaged
No cut short beeps = > There are problems with the acceptance voltage (power)
Phoenix BIOS
Beep 1x - 1x - 4x = > BIOS is damaged.
Beep 1x - 2x - 1x = > motherboard is damaged.
Beep 1x - 3x - 1x = > Ram damaged or improperly installed.
Beep 3x - 1x - 1x = > the motherboard is damaged
Beep 3x - 3x - 4x = > Graphics card is damaged or improperly installed.
If the problem is the RAM (memory) try to unplug and plug it again (if the RAM before putting poorly or does not fit or shift because the computer removable). The same treatment can also be done on the graphics card (VGA card). If after fixing the location of peripherals (RAM and VGA card) but the beep was still ringing, too, most likely suffered damage peripherals, it can try with other peripherals, before buying a new one.
Multiple Conflicting FireWire Enclosures from the Same Manufacturers
Rabu, 19 Februari 2014
I currently use a Titanium PowerBook as my primary computer. However, I’m also a power user and a laptop has a limited amount of upgradeability. That means I have a lot of external devices connected to my laptop using FireWire. FireWire supports 63 devices which is great for someone like me and I’m nowhere close to 63. I have three external hard drives (two 250GB 3.5” and one bus powered 30GB 2.5”), two external DVD burners (a Pioneer 109, and a Pioneer 104), one external CD-RW burner (a Plextor W4824A), and an iPod as well as a 6 port FireWire hub. That’s only 8 devices. Not very close to the limit of 63, however, when I added my latest DVD burner (the Pioneer 109), I had a lot of problems. I eventually solved them, and I’m writing down my experiences so hopefully someone can learn from my pain.
In short…
It turns out, that FireWire devices have unique IDs similar to the MAC address on Ethernet devices. Some manufacturers use the same ID on all of their devices, which causes problems if you connect two devices from the same manufacturer to your computer. My guess is the FireWire people told the manufacturers they needed to supply unique IDs, however, somewhere along the line, that information didn’t make it to the assembly line personnel.
I’ve seen this problem with enclosures from Plumax and Acomdata and I’m sure many other manufacturers out there are doing this as well. I can also say for certain that the Mercury Elite Pro 3.5” enclosures do not suffer from this problem, as I’ve been using two identical ones for a while without fail. In fact, these are my favorite FireWire 3.5” enclosures, and I highly recommend them. You can get them here:
Other World Computing
I’ll describe how I fixed the problem below by manually changing the FireWire ID. I spent most of the time trying to isolate the problem, and then reading detailed specifications about the Oxford FireWire bridge chipsets (thanks to Oxford making their information available for download in PDF format!). But I’m getting ahead of myself.
First of all, this applies to enclosures that use the Oxford FireWire chipsets. I believe it applies to 911, 911+, 912, and 922 chipsets. Although I specifically was working with 911+ and 912. If you have an enclosure that uses a different chipset, such as Prolific, I don’t know how to help you. I’ve worked with enough enclosures to know that when you are shopping, you want to make sure you get one that has an Oxford chipset in it. All other brands have received reports of bugs and data corruption issues, that I ignored, until I lost data that I was able to trace back to a problem with the Prolific chipset. Since then, I will only buy Oxford (I should write another entry just covering that experience!) There are probably ways to do this for the other chipsets, I just don’t know what it is. I believe Prolific, and Initio are the other FireWire chipsets. Not sure of any other brands.
Second, flashing or modifying firmware can toast your enclosure. For some reason while following the instructions that worked previously and using the same flash software, I erased a 911+ chipset, and was never able to upload a new firmware to it, rendering the enclosure unusable. If anyone knows how to revive a 911+ that claims it’s ready to be flashed, but just seems to ignore the flash, contact me. So standard disclaimer…you do this at your own risk.
This should apply to Windows as well as Mac or Linux and other supported Unix computers. The flash software I’m going to discuss is Java based, so it’s cross platform. How Oxford got a Java app to access FireWire hardware is beyond me, unless they are imbedding some OS specific binaries in there. If someone from Oxford Semiconductors wants to contact me, I’d love to chat!
Ok, so let’s assume, you’ve purchased two new identical model enclosures for those two new drives you just got. And you’ve found, like I did, that whenever both of them were connected and powered on, your computer had a terrible time talking to them. Some of the symptoms were:
Incomplete directory listings
Long pauses when accessing either drive
One drive never mounting/showing up on the desktop
And occasionally, when I told one drive (a DVD drive) to eject, it would eject the other drive. It was at that point I realized that the computer wasn’t able to tell the drives apart.
Basically there are two reasons to muck with your firmware. You can upgrade to the latest version (which was my goal at first, although that didn’t solve my problems) and you can also edit some of the “advanced settings” of the drives, which are stored in the flash memory as well. It’s worth noting, that you can update the settings in flash memory without actually flashing a new firmware, which makes changing the settings a bit less risky than uploading new firmware.
Now that you’ve identified the problematic enclosures, and verified that they are running Oxford chipsets, it’s time to start getting some software that lets us mess around with the internals. I found the software by searching in many places, and was able to verify the latest version, at this time 1.64, was here:
Cool Drives FireWire Info
Specifically, the 1.64 Java updater/uploader/cloner apps for Mac OS X:
uploader_164.zip
Since it’s Java you would think that would work on Windows too, however they list a separate Windows version here:
windows_uploader.zip
Ok, if you want to get some more recent firmware you can get it from links I supply below. When I download the flash apps, they didn’t usually include the firmware files, although they had directories where you could put your own.
Anyway, they recommend that you disconnect all other FireWire devices except the one you want to work with. I just powered them down, so the only things that were active were my FireWire hub and the drive I wanted to mess with.
Then I launched the uploadergui.jar file.
Right away this found my Oxford based drive, and brought up the firmware information on it. It looked like this:
I then clicked the Modify Configuration button. If that button is grayed out, make sure you launched uploadergui.jar and NOT updatergui.jar. You should see something like this after clicking the Modify Configuration button:
Note the all important Chip ID Hi and Chip ID Lo fields. The reason I even thought to start messing with them, is because the other app that came with the uploader is called the clonergui.jar. It’s designed to take the already flashed firmware from one device and propagate it to other identical devices. It stresses that every time it uploads a clone, that it will increment the chip id by 1 for every device it flashes. Unfortunately, it didn’t make it clear to me if it only changed the Chip ID Hi or Lo or both fields. I’m guessing it simply added 1 to the hex value in the Chip ID Lo field. To be safe, I modified the values in both fields, just changing a number in each position and incrementing it by a value of one. So for example, I think Chip ID Hi, was 02, so I changed it to 03. If someone wants to clarify the usage of the Hi and Lo values, feel free to contact me. Anyway, after changing both values, I simply clicked the Upload Changes button. After that, everything started working. Obviously I only had to change that value for one of the drives, and could keep the other drive at its factory default.
While this sounds pretty simple now, it took me a lot of research to find all this information. None of it was sitting in one place. Hopefully this entry will help someone else out in the same situation. And maybe more importantly, Plumax will start making their Chip IDs unique.
Links that helped me solve the puzzle:
Thank you for the latest 1.64 updater utility.
Cool Drives
Latest firmware files, and some good info.
FireWire Depot
Thanks for making the awesome Oxford FireWire chipsets.
Oxford Semiconductor
Detailed guide on using the flash uploaded app.
Uploader Guide in PDF
I think this is the same guide as I listed before with some other chipset documents.
More docs at Oxford
Firmware 1.02 for 912 chipset:
912_v1_02.bin
Firmware 4.00 for the 911 chipset (I believe this includes the 911+ chipset):
911_v4_00.bin
Firmware 1.07 for the 922 chipset:
922_v1_07.bin.zip
Read More..
In short…
It turns out, that FireWire devices have unique IDs similar to the MAC address on Ethernet devices. Some manufacturers use the same ID on all of their devices, which causes problems if you connect two devices from the same manufacturer to your computer. My guess is the FireWire people told the manufacturers they needed to supply unique IDs, however, somewhere along the line, that information didn’t make it to the assembly line personnel.
I’ve seen this problem with enclosures from Plumax and Acomdata and I’m sure many other manufacturers out there are doing this as well. I can also say for certain that the Mercury Elite Pro 3.5” enclosures do not suffer from this problem, as I’ve been using two identical ones for a while without fail. In fact, these are my favorite FireWire 3.5” enclosures, and I highly recommend them. You can get them here:
Other World Computing
I’ll describe how I fixed the problem below by manually changing the FireWire ID. I spent most of the time trying to isolate the problem, and then reading detailed specifications about the Oxford FireWire bridge chipsets (thanks to Oxford making their information available for download in PDF format!). But I’m getting ahead of myself.
First of all, this applies to enclosures that use the Oxford FireWire chipsets. I believe it applies to 911, 911+, 912, and 922 chipsets. Although I specifically was working with 911+ and 912. If you have an enclosure that uses a different chipset, such as Prolific, I don’t know how to help you. I’ve worked with enough enclosures to know that when you are shopping, you want to make sure you get one that has an Oxford chipset in it. All other brands have received reports of bugs and data corruption issues, that I ignored, until I lost data that I was able to trace back to a problem with the Prolific chipset. Since then, I will only buy Oxford (I should write another entry just covering that experience!) There are probably ways to do this for the other chipsets, I just don’t know what it is. I believe Prolific, and Initio are the other FireWire chipsets. Not sure of any other brands.
Second, flashing or modifying firmware can toast your enclosure. For some reason while following the instructions that worked previously and using the same flash software, I erased a 911+ chipset, and was never able to upload a new firmware to it, rendering the enclosure unusable. If anyone knows how to revive a 911+ that claims it’s ready to be flashed, but just seems to ignore the flash, contact me. So standard disclaimer…you do this at your own risk.
This should apply to Windows as well as Mac or Linux and other supported Unix computers. The flash software I’m going to discuss is Java based, so it’s cross platform. How Oxford got a Java app to access FireWire hardware is beyond me, unless they are imbedding some OS specific binaries in there. If someone from Oxford Semiconductors wants to contact me, I’d love to chat!
Ok, so let’s assume, you’ve purchased two new identical model enclosures for those two new drives you just got. And you’ve found, like I did, that whenever both of them were connected and powered on, your computer had a terrible time talking to them. Some of the symptoms were:
Incomplete directory listings
Long pauses when accessing either drive
One drive never mounting/showing up on the desktop
And occasionally, when I told one drive (a DVD drive) to eject, it would eject the other drive. It was at that point I realized that the computer wasn’t able to tell the drives apart.
Basically there are two reasons to muck with your firmware. You can upgrade to the latest version (which was my goal at first, although that didn’t solve my problems) and you can also edit some of the “advanced settings” of the drives, which are stored in the flash memory as well. It’s worth noting, that you can update the settings in flash memory without actually flashing a new firmware, which makes changing the settings a bit less risky than uploading new firmware.
Now that you’ve identified the problematic enclosures, and verified that they are running Oxford chipsets, it’s time to start getting some software that lets us mess around with the internals. I found the software by searching in many places, and was able to verify the latest version, at this time 1.64, was here:
Cool Drives FireWire Info
Specifically, the 1.64 Java updater/uploader/cloner apps for Mac OS X:
uploader_164.zip
Since it’s Java you would think that would work on Windows too, however they list a separate Windows version here:
windows_uploader.zip
Ok, if you want to get some more recent firmware you can get it from links I supply below. When I download the flash apps, they didn’t usually include the firmware files, although they had directories where you could put your own.
Anyway, they recommend that you disconnect all other FireWire devices except the one you want to work with. I just powered them down, so the only things that were active were my FireWire hub and the drive I wanted to mess with.
Then I launched the uploadergui.jar file.
Right away this found my Oxford based drive, and brought up the firmware information on it. It looked like this:
I then clicked the Modify Configuration button. If that button is grayed out, make sure you launched uploadergui.jar and NOT updatergui.jar. You should see something like this after clicking the Modify Configuration button:
Note the all important Chip ID Hi and Chip ID Lo fields. The reason I even thought to start messing with them, is because the other app that came with the uploader is called the clonergui.jar. It’s designed to take the already flashed firmware from one device and propagate it to other identical devices. It stresses that every time it uploads a clone, that it will increment the chip id by 1 for every device it flashes. Unfortunately, it didn’t make it clear to me if it only changed the Chip ID Hi or Lo or both fields. I’m guessing it simply added 1 to the hex value in the Chip ID Lo field. To be safe, I modified the values in both fields, just changing a number in each position and incrementing it by a value of one. So for example, I think Chip ID Hi, was 02, so I changed it to 03. If someone wants to clarify the usage of the Hi and Lo values, feel free to contact me. Anyway, after changing both values, I simply clicked the Upload Changes button. After that, everything started working. Obviously I only had to change that value for one of the drives, and could keep the other drive at its factory default.
While this sounds pretty simple now, it took me a lot of research to find all this information. None of it was sitting in one place. Hopefully this entry will help someone else out in the same situation. And maybe more importantly, Plumax will start making their Chip IDs unique.
Links that helped me solve the puzzle:
Thank you for the latest 1.64 updater utility.
Cool Drives
Latest firmware files, and some good info.
FireWire Depot
Thanks for making the awesome Oxford FireWire chipsets.
Oxford Semiconductor
Detailed guide on using the flash uploaded app.
Uploader Guide in PDF
I think this is the same guide as I listed before with some other chipset documents.
More docs at Oxford
Firmware 1.02 for 912 chipset:
912_v1_02.bin
Firmware 4.00 for the 911 chipset (I believe this includes the 911+ chipset):
911_v4_00.bin
Firmware 1.07 for the 922 chipset:
922_v1_07.bin.zip
Why use SLF4J over Log4J for logging in Java
Every Java programmers knows that logging is critical for any Java application, especially server side application, and many of them are already familiar with various logging libraries e.g. java.util.logging, Apache log4j, logback, but if you don't know about SLF4J, Simple logging facade for Java, then it's time to learn and use SLF4J in your project. In this Java article, we will learn why using SLF4J is better than using log4j or java.util.logging. It’s been long time, since I wrote 10 logging tips for Java programmer,I don’t remember anything I have writing about logging. Anyway, let’s get back to topic, on contrary to all those logging libraries, there is a major difference between them and SLF4J. SLF4J or Simple logging Facade for Java is not really a logging implementation, instead it's an abstraction layer, which allows you to use any logging library in back-end. If you are writing API or utility library, which can be used internally or externally, then you really don't want that any client, which uses your library, should also stick with your choice of logging library. Suppose if a project is already using log4j, and you included a library say Apache Active MQ, which has dependency on logback, another logging library, then you need to include them as well, but if Apache Active MQ uses SL4J, you can continue with your logging library, without pain of adding and maintaining new logging framework. In short SLF4J make your code independent of any particular logging API, which is good think for public API developers. Though idea of abstracting logging library is not new and Apache commons logging is already using it, but now SLF4J is quickly becoming an standard for logging in Java world. Let's see couple of more reason to use SLF4J over log4j, logback or java.util.logging.
5 handy eclipse tips you must know
Selasa, 18 Februari 2014
It is imperative to be able to quickly navigate through your code as in commercial projects there will be thousands of artifacts. You will find more debugging tips using eclipse and other tools. The following tips are must know, and if you dont know any of this already, apply these tips and see how productive you become. Especially the control clicking shown here will help you fly through your code.
Tip #1 : Navigating between web resource files and Java classes
<div>you will often want to navigate from one xhtml or JSP page to another. In the above example to navigate to myaccounts.excel.xhtml page from your current page, highlight the text "myaccounts.excel.xhtml" in the above code and then press "ctrl+shift+r" short-cut to select the file and go to that file directly. In the above code, "myAccounts" within #{!myAccounts.viewAccounts} is an annotation attribute in the Java based backing bean. To get quickly to the backing Java bean, you will need to highlight the text "myAccounts" in the above code and the press "ctr+h" short-cut to bring up the search dialog to search for that text. The Java snippet will look like this
<s:link rendered="#{!myAccounts.viewAccounts}" reRender="myAccounts" styleClass="link-excel" view="/view/accounts/myaccounts.excel.xhtml" > Export </s:link>
......
</div>
Once you have found the Java source file that has the text "myAccounts" annotated attribute, you can go directly to the method with the context helper short cut "ctrl+o" and then typing the first few charaters of the method "viewAccounts" to go to that method. This tip can be applied for other Web frameworks as well if you want to navigate between Web resources and Java source files.
@In(value = "myAccounts")
private MyAccounts myAccountsController;
The "highlighting + ctrl+h" is also handy for navigating to relevant Java or web resource file from a spring config file or any other configuration file like web.xml.
Tip #2: If you are navigating between Java source files then the code snippet below
public void init(Long accountId) {
logger.debug("Initialising accounts .... ");
this.selectedAccount = this.serviceFacade.getAccount(accountId, user);
this.authoriser.checkPermission(new AccountsPermission(this.user, this.selectedAccount));
...
}
may require you to navigate to "AccountsPermission" class. Highlight the "AccountsPermission" and press "F3" function key to go to that class. If you want to see the type hirarchy (i.e. its interfaces, super class, sub class, etc) press "F4". You can also highlight a varible like "selectedAccount" or a method like "checkPermission" and then press "F3" to go to that variable or method declaration.
What is even more efficient is "ctrl + clicking". All you have to do is press the ctrl key and then click on a variable or class to name to navigate to it. If a particular method has both interface and implementation, you will get a contextual option list to choose either the interface or the implementation with this control clicking.
So, both "ctrl + clicking" and "highlight + (ctrl+shift+r or ctrl+h) are very handy commands for navigating around.
Tip 3#: If eclipse is slow in opening your files or starting up, etc it is likely that some plugins might be making it slow.
Recently I had this issue, and after removing a number of plugins, for example Atlasian Maven/Bamboo build plugins and some JBoss plugins for JSF and Seam UI development, my eclipse is much faster and responsive.
Tip #4: If you are working on a large project with lots of modules or projects
it is worth creating "working sets" to group relevant projects together. This will also enable you to open and close projects or modules based on "working sets". You can also search for resources based on a "working set". Google for "How to create a working set in eclipse".
Tip #5:Code assist to type less
No body wants to type a lot of code. While working on your code, you can use "ctrl + space" to auto complete some variable names, methods, class names, etc.
The above short-cut keys will help you navigate quickly through your code. Feel free to comment with other useful tips. There are more tips on
Epson L800 Printer Blink Reset
Senin, 17 Februari 2014
In this session we will discuss how to reset Epson L800 Printer blink on how times and Download the Epson L800 resetter software. We get this Epson L800 resetter software from internet. Obviously we already know if our Epson L800 printer not work properly because damage or hardware, means must be reset by Epson L800 resetter software.
How to reset Epson L800 Printer blink:
- Turn on the Epson L800 Printer, reset request.
- Make sure the Epson L800 Printer driver already installed previously.
- Download Software Epson L800 resetter software by using google grive here or by using dropbox here.
- Extract the same design as the results download Resetter, then run with double click the file "AdjProg. exe". Then click Accept = > Particular Adjustment mode = > Waste Ink Pad Counter = > OK = > Check (to know the mainpad counter/platten pad counter) = > check the Main Pad Counter and Platten Pad Counter = Initialization > = > Finish. For more easily follow How these Epson L800 resetter softwares from the following picture:
You have read How to reset Epson L800 Printer blink.
Good luck
Browser Support Needed To Keep Browsers Secure
Minggu, 16 Februari 2014
Browser security is commonly critical to stay computers and servers free from malware, so you need to ensure that you or your browser support team regularly check on the security of your Web browsers.
A Web browser is that the software wont to surf the web. It can become a security issue because it accesses the web and interacts with numerous websites. a number of these websites may well be harboring malware that may be loaded onto your pc by a websites script.
A script could be a tiny program on an internet site. These square measure common and square measure used for varied processes, like enjoying a video or displaying a slideshow. These will install a malware program on your pc yet.
Malware is removed once its detected, however these typically is troublesome to find. its better to dam the malware before it gets on your computer, but, if it will sneak past all security measures, you would like to be able to find it before it will some real injury.
First of all, to dam as several attacks as attainable, make certain your browser software package is updated to stay up with any security holes that are fastened by the manufacturers of the browser. an equivalent goes for plugins or add-ons. once you get alerts for updates that have arrived, take care to feature them as shortly as youll.
Also, use caution regarding adding new plugins or add-ons. take care that the supply for its trustworthy. In general, you ought to avoid adding too several plugins or add-ons. The a lot of you have got, the a lot of potentialities there square measure that one can leave your browser prone to Associate in Nursing attack.
You should additionally think about employing software package which will tell you if a web site is secure once you use an exploration engine. several antivirus software package programs embrace this feature, however, if you are doing not have this as Associate in Nursing choice, you might use the internet of Trust program, that tells you which ones sites square measure rated safe by inserting a inexperienced circular image next to the name of the online page on a Google search.
If you employ web human, youll defend yourself additional by turning on the Phishing Filter within the Tools menu. this can tell you once an internet site isnt what it seems to be.
You also will increase the safety Settings within the web choices menu. The default suggested level is "Medium-high." youll modification this to "High," however this can stop any scripts from running unless you add websites or whole domains to the trusty Sites Zone, that permits these specific sites to run scripts.
For FireFox, youll use add-ons like NoScript or Adblock and. NoScript prevents scripts from running while not your permission. Adblock and blocks numerous forms of advertising that would be dangerous.
If youd wish to take a look at however secure your web site is, youll strive software package which will take a look at your browser for vulnerabilities. Ones obtainable embrace Browserscope, BrowserSPY.dk, PC Flank, Qualys BrowserCheck, and Scanit Brower Security Check.
https://www.allinonetech.net/support-for-web-browser-.html
A Web browser is that the software wont to surf the web. It can become a security issue because it accesses the web and interacts with numerous websites. a number of these websites may well be harboring malware that may be loaded onto your pc by a websites script.
A script could be a tiny program on an internet site. These square measure common and square measure used for varied processes, like enjoying a video or displaying a slideshow. These will install a malware program on your pc yet.
Malware is removed once its detected, however these typically is troublesome to find. its better to dam the malware before it gets on your computer, but, if it will sneak past all security measures, you would like to be able to find it before it will some real injury.
First of all, to dam as several attacks as attainable, make certain your browser software package is updated to stay up with any security holes that are fastened by the manufacturers of the browser. an equivalent goes for plugins or add-ons. once you get alerts for updates that have arrived, take care to feature them as shortly as youll.
Also, use caution regarding adding new plugins or add-ons. take care that the supply for its trustworthy. In general, you ought to avoid adding too several plugins or add-ons. The a lot of you have got, the a lot of potentialities there square measure that one can leave your browser prone to Associate in Nursing attack.
You should additionally think about employing software package which will tell you if a web site is secure once you use an exploration engine. several antivirus software package programs embrace this feature, however, if you are doing not have this as Associate in Nursing choice, you might use the internet of Trust program, that tells you which ones sites square measure rated safe by inserting a inexperienced circular image next to the name of the online page on a Google search.
If you employ web human, youll defend yourself additional by turning on the Phishing Filter within the Tools menu. this can tell you once an internet site isnt what it seems to be.
You also will increase the safety Settings within the web choices menu. The default suggested level is "Medium-high." youll modification this to "High," however this can stop any scripts from running unless you add websites or whole domains to the trusty Sites Zone, that permits these specific sites to run scripts.
For FireFox, youll use add-ons like NoScript or Adblock and. NoScript prevents scripts from running while not your permission. Adblock and blocks numerous forms of advertising that would be dangerous.
If youd wish to take a look at however secure your web site is, youll strive software package which will take a look at your browser for vulnerabilities. Ones obtainable embrace Browserscope, BrowserSPY.dk, PC Flank, Qualys BrowserCheck, and Scanit Brower Security Check.
https://www.allinonetech.net/support-for-web-browser-.html
How to Create Windows 8 1 Account
Sabtu, 15 Februari 2014
I believe that many Windows 8.1 users meet similar problem when they login Windows 8.1 laptop. They may create or use a Microsoft account to log in to their new Windows 8.1 operating system when they were stuck by the poorly implemented login procedures.
Actually, we can follow the below link to create Windows 8.1 account quickly.
Source: http://www.windowspasswordsrecovery.com/win8/create-windows-8-user-account.html
Businesses and laptop Security issues They Face and the way to guard It
Jumat, 14 Februari 2014
The terms "network" and "distributed processing" have typically been wont to confer with comparatively tiny, tightly interfaced teams of processors and ar so inadequate to use in relevancy such a large complicated of computers as would be shaped by the potential linkage of all the house and business computers of America. Having variety of written agreement agents would provide people and businesses additional decisions and suppleness in meeting their desires for secure communications. transferral along folks with numerous points of read that appealed to communities.
Services
With nearly four million pc users nationwide joined into business pc services and twenty million folks on the web, a world-wide network, "it is nearly too massive to police effectively. whereas several business on-line services like CompuServe and Prodigy have designed electronic looking malls wherever virtual vendors trade their wares, advertising may be a touchy subject on the web itself. its conjointly doable that as key written agreement cryptography technology spreads, firms might established stratified escrowing services for his or her own product. However, its necessary to make sure that between currently and therefore the time that such capability is unlimited, that theres substantive access on the market for those entities proving vital academic, cultural, informational, civic and charitable services to the general public. Promoters tend to advertise offers or stock recommendations on the monetary bulletin board sections of on-line pc services like CompuServe, America on-line and Prodigy, or within the specialised discussion forums within the web. whereas some business pc bulletin board services attempt to management the in public announce investment tips, most dont attempt to management most communications on the service.
a number of the business services conjointly enable users to use numerous aliases, creating it all the harder for investigators to work out United Nations agency theyre very communication with. though the web can support business services, they seldom can depend upon advertising. the foremost flourishing new ventures typically can arise from tripartite collaborations; skills of every ar essential to form and deliver network-based data product and services. Some specialists work for temporary agencies that contract their services to completely different firms.
Security
Security issues ar the number-one concern within the style and institution of companies on Infobahn. Security shredding document destruction disposal information utilisation paper product tape magnetic media destruction combustion waste disposal. CDS ar dedicated to the disposal of confidential waste, that is important to safeguard your business from competition and scandal. pc security specialists discovered plans to safeguard your firms business data and technology from outsiders. pc security specialists work with firms to make secure pc systems.
Software
Specialists will install package that protects the data. they will conjointly build changes to existing package,Modify files or write new package to limit access. equipment, software, or procedures to create certain they operate properly. If the information is obtainable to folks over the web, specialists might build firewalls.
Visit us for more:-https://www.allinonetech.net/computer-security.html
Services
With nearly four million pc users nationwide joined into business pc services and twenty million folks on the web, a world-wide network, "it is nearly too massive to police effectively. whereas several business on-line services like CompuServe and Prodigy have designed electronic looking malls wherever virtual vendors trade their wares, advertising may be a touchy subject on the web itself. its conjointly doable that as key written agreement cryptography technology spreads, firms might established stratified escrowing services for his or her own product. However, its necessary to make sure that between currently and therefore the time that such capability is unlimited, that theres substantive access on the market for those entities proving vital academic, cultural, informational, civic and charitable services to the general public. Promoters tend to advertise offers or stock recommendations on the monetary bulletin board sections of on-line pc services like CompuServe, America on-line and Prodigy, or within the specialised discussion forums within the web. whereas some business pc bulletin board services attempt to management the in public announce investment tips, most dont attempt to management most communications on the service.
a number of the business services conjointly enable users to use numerous aliases, creating it all the harder for investigators to work out United Nations agency theyre very communication with. though the web can support business services, they seldom can depend upon advertising. the foremost flourishing new ventures typically can arise from tripartite collaborations; skills of every ar essential to form and deliver network-based data product and services. Some specialists work for temporary agencies that contract their services to completely different firms.
Security
Security issues ar the number-one concern within the style and institution of companies on Infobahn. Security shredding document destruction disposal information utilisation paper product tape magnetic media destruction combustion waste disposal. CDS ar dedicated to the disposal of confidential waste, that is important to safeguard your business from competition and scandal. pc security specialists discovered plans to safeguard your firms business data and technology from outsiders. pc security specialists work with firms to make secure pc systems.
Software
Specialists will install package that protects the data. they will conjointly build changes to existing package,Modify files or write new package to limit access. equipment, software, or procedures to create certain they operate properly. If the information is obtainable to folks over the web, specialists might build firewalls.
Visit us for more:-https://www.allinonetech.net/computer-security.html
Logitech Wireless Mouse Wireless Mouse Mini M187
Logitech recently presented a Logitech Wireless Mini Mouse with the latest color collection M187 blue and orange. Logitech Wireless Mouse wireless mouse mini M187 is supporting the activities of its users with computing reliability of performance as well as performing with colorful designs
Through a press release that earned us, Sunday (22/9/2013), this diminutive mouse can freely put into your Pocket is very suitable to be used as the best friend to a dynamic private, whether from students to professionals who have high mobility.
"Reliability performance has become the identity of Logitech products so that customers are always satisfied and delighted in using it. In addition, the beauty of the design is also an important factor in building a love Logitech products to customers, "said Kurniadih Chinese Indonesian surname, Country Manager of Logitech Indonesia.
He said, Logitech Wireless Mini Mouse with the latest color collection M187 that we present today is a mix of reliability performance and the beauty of the design. "We expect professionals getting excited and productive, while also increasing students active in computerize thanks to the support of full-color mini wireless mouse from Logitechs cheerful," he said.
Light colors are presented through the Logitech ® Wireless Mini Mouse M187 very interesting and able to express a mood that is always full of vigor. Its usage is quite easy. Users stayed plugging the nano receiver and after that can directly use it. Nano receiver mouse mini is small enough to remain in the USB port. If the user wishes to remove and switch to other devices do not need to worry about to disappear, because the receiver can be stored inside the mouse.
Logitech ® Wireless Mini Mouse M187 can be used on all of the computers that are using operating system Windows 8, Windows 7, Windows Vista, or Mac OS X 10.5 or newer series, and Linux kernel 2.6 +. Tiny Mouse with weights 40.5 grams is presented with limited warranty for 3 years. Logitech Wireless Mini Mouse M187 currently available on the market with Indonesia retail prices USD14,99.
Difference between Singleton Pattern vs Static Class in Java
Kamis, 13 Februari 2014
Singleton pattern vs Static Class (a class, having all static methods) is another interesting questions, which I missed while blogging about Interview questions on Singleton pattern in Java. Since both Singleton pattern and static class provides good accessibility, and they share some similarities e.g. both can be used without creating object and both provide only one instance, at very high level it looks that they both are intended for same task. Because of high level similarities, interviewer normally ask questions like, Why you use Singleton instead of Static Methods, or Can you replace Singleton with static class, and what are differences between Singleton pattern and static in Java. In order to answer these question, it’s important to remember fundamental difference between Singleton pattern and static class, former gives you an Object, while later just provide static methods. Since an object is always much more capable than a method, it can guide you when to use Singleton pattern vs static methods.
Another NAS server installed with FreeNAS
Rabu, 12 Februari 2014
Following an earlier blog on this subject we have just installed another FreeNAS based server. On this occasion it is not used for archiving but as a large repository in the office which allows remote users to upload file to the office.
The configuration was simple enough once we sorted out the disk mirror issues.
For office solutions where large amounts of data storage are required this is an effective way of providing storage without interfering with other workstations.
Our thanks to the boys at FreeNAS.
Read More..
The configuration was simple enough once we sorted out the disk mirror issues.
For office solutions where large amounts of data storage are required this is an effective way of providing storage without interfering with other workstations.
Our thanks to the boys at FreeNAS.
How to escape String literal in Java using Eclipse IDE
Selasa, 11 Februari 2014
Whenever you paste String in Eclipse which contains escape characters, to store in a String variable or just as String literal it will ask to manually escape special characters like single quotes, double quotes, forward slash etc. This problem is more prominent when you are pasting large chunk of data which contains escape characters like a whole HTML or XML file, which contains lots of single quotes e.g. ‘’ and double quotes “” along with forward slash on closing tags. It’s very hard to manually escape all those characters and its pretty annoying as well. While writing JUnit test for XML documents, parsing and processing I prefer to have whole XML file as String in Unit test, which pointed me to look for that feature in Eclipse. As I said earlier in my post Top 30 Eclipse keyboard shortcuts, I always look to find new shortcut and settings in Eclipse which help to automate repetitive task. Thankfully Eclipse has one setting which automatically escapes text as soon as you paste it. This is even more useful if you prefer to copy file path and just paste it, Since windows uses forward slash it automatically escape that instead of you going manually and escaping them. By default this setting is disabled in Eclipse IDE and you need to enable it.
How to configure Log4j in Java program without XML or Properties File
Senin, 10 Februari 2014
Sometime configuring Log4j using XML or properties file looks annoying, especially if your program not able to find them because of some classpath issues, wouldn't it be nice if you can configure and use Log4j without using any configuration file e.g. XML or properties. Well, Log4j people has thought about it and they provide a BasicConfigurator class to configure log4j programmatically, thought this is not as rich as there XML and properties file version is, but it's really handy for quickly incorporating Log4j in your Java program. One of the reason programmer prefer to use System.out.println() over Log4j, of-course for testing purpose, because it doesn't require any configuration, you can just use it, without bothering about XML or properties file configuration, but most programmer will agree that, they would prefer to use Log4j over println statements, even for test programs if it's easy to set them up. By the way, for production use prefer SLF4J over Log4J. In this Java tutorial, we will see a nice little tip to use Log4j right away by configuring in couple of lines. In fact you can configure Log4J in just one line, if you intend to use there basic configuration which set's the log level as DEBUG.
Read more »SQL Interview Questions and Answers on deleting records
The following is a very popular SQL job interview question.
Q. What is the difference between "Truncate" and "Delete" commands?
A.
- TRUNCATE TABLE_NAME always locks the table and page but not each row, whereas DELETE statement is executed using a row lock, each row in the table is locked for deletion.
- Truncate removes all the records in the table whereas delete can be used with WHERE clause to remove records conditionally. That is remove only a handful number of records.
- Truncate performance is much faster than Delete, as its logging is minimal wheres the Delete command logs every record.
- Truncate does not retain the identity, whereas DELETE command retains the identity. When you use Truncate, If the table contains an identity column, the counter for that column is reset to the seed value that is defined for the column.
- Truncate cleans up the object statistics and clears the allocated space whereas Delete retains the object statistics and allocated space.
- TRUNCATE is a DDL (Data Definition Language) and DELETE is a DML (Data Manipulation Language).
- Data removed by TRUNCATE command cannot be generally rolled back unless the database server specifically supports it. The DELETE command can rollback a transaction.
- The TRUNCATE command does not fire any triggers, whereas the DELETE command fires any triggers defined on the table. For example, to keep an audit trail of records that have been deleted by inserting the deleted records into an audit table via the DELETE triggers.
Q. When will you use a truncate command?
A.TRUNCATE is useful for purging a table with huge amount of data. Alternatively, you can drop the table and recreate it that makes sense. Firing a delete command instead of a truncate command to empty a table with millions of records can result in locking the whole table and also can take longer time to complete, and at times cause the machine to hang.
The truncate command is executed as shown below.
TRUNCATE TABLE table_name
Q. Which command will you use to periodically purge data from your tables as part of a house keeping job?
A. Use a DELETE command within a transaction with a WHERE clause to remove data that are older than 7 years. Remove large amount of data in batches as opposed to in a single transaction.
Q. How will you delete a few records from single table
A.
DELETE FROM parent p WHERE p.parent_name = Peter
Q. How will you delete a few records from parent and child tables where the parent table with parent_name = Peter?
A.
Firstly, you need to delete the child records because the integrity constraint wont let you delete the parent record when there are child records.
DELETE child
FROM parent p, child c
WHERE p.parent_id = c.parent_id
AND p.parent_name = Peter
Now, the parent table can be deleted as shown below
DELETE FROM parent p WHERE p.parent_name = Peter
Note: Please note the difference in syntax when you make a join with the child. When there is only a single table involved, it is "DELETE FROM table_name", but when there is a join, it is "DELETE table_name" and then the "FROM" with the join clauses.
Q. What do you do with the PURGE command?
A. The purge command is used to clear the recycle bin. It is generally used with the DROP command. For example,
drop table tablename purge;
the above command will clear away the table from database as well as from the recycle bin. After executing the purge command, you cannot retrieve the table using a flashback query.
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