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What is database pooling?
...cally, opening a database connection is an expensive operation, especially if the database is remote. You have to open up network sessions, authenticate, have authorisation checked, and so on. Pooling keeps the connections active so that, when a connection is later requested, one of the active ones ...
What's the difference between @JoinColumn and mappedBy when using a JPA @OneToMany association
What is the difference between:
8 Answers
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Comment the interface, implementation or both?
... document the interface
on implementation, document the implementation specifics
Java specific: when documenting the implementation, use {@inheritDoc} tag to "include" javadocs from the interface.
For more information:
Official javadoc documentation
Some unofficial advice.
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How to randomly pick an element from an array
...me you run the function: the random generator is supposed to have history. If it haven't, it's extremely predictable. It's not a problem at all in this case — but it should be mentioned that array[(int)(System.currentTimeMillis() % array.length)] is just as good as the proposed solution.
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How to list only top level directories in Python?
...to get the real path):
>>> [ name for name in os.listdir(thedir) if os.path.isdir(os.path.join(thedir, name)) ]
['ctypes', 'distutils', 'encodings', 'lib-tk', 'config', 'idlelib', 'xml', 'bsddb', 'hotshot', 'logging', 'doc', 'test', 'compiler', 'curses', 'site-packages', 'email', 'sqlite3'...
Check folder size in Bash
I'm trying to write a script that will calculate a directory size and if the size is less than 10GB, and greater then 2GB do some action. Where do I need to mention my folder name?
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Android - implementing startForeground for a service?
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I'd start by completely filling in the Notification. Here is a sample project demonstrating the use of startForeground().
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How may I reference the script tag that loaded the currently-executing script?
...t;/script>
Benefits
Simple and explicit. Reliable.
Don't need to modify the script tag
Works with asynchronous scripts (defer & async)
Works with scripts inserted dynamically
Problems
Will not work in older browsers and IE.
Does not work with modules <script type="module">
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Java rounding up to an int using Math.ceil
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int n = a / b + ((a % b == 0) ? 0 : 1);
You do a / b with always floor if a and b are both integers. Then you have an inline if-statement witch checks whether or not you should ceil instead of floor. So +1 or +0, if there is a remainder with the division you need +1. a % b == 0 checks for the re...
Questions every good .NET developer should be able to answer? [closed]
...ompile a list/catalog of good questions, a kind of minimum standard to see if the applicants are experienced. So, my question is:
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