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Lock, mutex, semaphore… what's the difference?
...nly one thread to enter the part that's locked and the lock is not shared with any other processes.
A mutex is the same as a lock but it can be system wide (shared by multiple processes).
A semaphore does the same as a mutex but allows x number of threads to enter, this can be used for example to ...
Detect if value is number in MySQL
...k in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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MySQL vs MongoDB 1000 reads
I have been very excited about MongoDb and have been testing it lately. I had a table called posts in MySQL with about 20 million records indexed only on a field called 'id'.
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What is the difference between an interface and abstract class?
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Interfaces
An interface is a contract: The person writing the interface says, "hey, I accept things looking that way", and the person using the interface says "OK, the class I write looks that way".
An interface is an empty shell. There are only the signatures of the methods,...
A potentially dangerous Request.Path value was detected from the client (*)
...acter is not allowed in the path of the URL, but there is no problem using it in the query string:
http://localhost:3286/Search/?q=test*
It's not an encoding issue, the * character has no special meaning in an URL, so it doesn't matter if you URL encode it or not. You would need to encode it usin...
Why is $$ returning the same id as the parent process?
I have problem with Bash, and I don't know why.
Under shell, I enter:
6 Answers
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Is well formed without a ?
Is it valid to have <input> without it being in a <form> ?
7 Answers
7
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What does it mean for a data structure to be “intrusive”?
...ive used to describe data structures like lists and stacks, but what does it mean?
2 Answers
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How do I hide a menu item in the actionbar?
I have an action bar with a menuitem. How can I hide/show that menu item?
24 Answers
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Build Eclipse Java Project from Command Line
...urce\MyProject\workspace" -application org.eclipse.jdt.apt.core.aptBuild
It uses the jdt apt plugin to build your workspace automatically. This is also known as a 'Headless Build'. Damn hard to figure out. If you're not using a win32 exe, you can try this:
java -cp startup.jar -noSplash -data "...