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What is Persistence Context?

...erence/en/html/architecture.html In Java EE, a persistence context is normally accessed via an EntityManager. http://docs.oracle.com/javaee/6/api/javax/persistence/EntityManager.html The various states an entity can have and the transitions between these are described below: http://docs.jboss.or...
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What is reflection and why is it useful?

... say you have an object of an unknown type in Java, and you would like to call a 'doSomething' method on it if one exists. Java's static typing system isn't really designed to support this unless the object conforms to a known interface, but using reflection, your code can look at the object and fin...
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How much size “Null” value takes in SQL Server

... The smallest addressable unit of memory in most computer systems is one byte (typically 8 bits). So in reality, a bit takes a byte. Great answer Mark: +1. – JohnB Sep 16 '10 at 22:23 ...
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Fatal error: Class 'ZipArchive' not found in

I have a problem that I install 'Archive_Zip 0.1.1' on Linux server, but when I try to run the script to create the zip file it gives the fatal error ...
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PHP PDO returning single row

... Do you really need to LIMIT 1 all the time though? Knowing that you're selecting a UNIQUE value comes to mind. – Super Cat Feb 1 '17 at 3:10 ...
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Should Github be used as a CDN for javascript libraries? [closed]

.... The last one means less total work for everybody, so it's clearly a win all around, and is more likely the more often we (developers) rely on the CDNs to serve our javascript. ...
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How can I install pip on Windows?

pip is a replacement for easy_install . But should I install pip using easy_install on Windows? Is there a better way? ...
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Why use make over a shell script?

...t would be a lot more work (explicitly checking the last-modified dates on all the files, etc.) The only obvious alternative with a shell script is to rebuild everything every time. For tiny projects this is a perfectly reasonable approach, but for a big project a complete rebuild could easily take ...
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Convert NSArray to NSString in Objective-C

... Won't this accomplish the same thing as calling [array description]? – TechZen Dec 1 '09 at 20:55 10 ...
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Setting element of array from Twig

... This is so silly. Why doesn't twig allow the ability to set array values? – Matt Cavanagh Aug 2 '16 at 8:48 1 ...