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Why are variables “i” and “j” used for counters?
...a formal sum like this can be construed as degrees of freedom [directions, by another name] of the equation.
– David
Dec 5 '10 at 19:57
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How to sort the result from string_agg()
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With postgres 9.0+ you can write:
select string_agg(product,' | ' order by product) from "tblproducts"
Details here.
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What does mvn install in maven exactly do
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As you might be aware of, Maven is a build automation tool provided by Apache which does more than dependency management. We can make it as a peer of Ant and Makefile which downloads all of the dependencies required.
On a mvn install, it frames a dependency tree based on the project configur...
How do I convert a git repository to mercurial?
... share the project with other java developers and hg seems to be most used by them.
9 Answers
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Is iterating ConcurrentHashMap values thread safe?
...t each iterator you obtain from a ConcurrentHashMap is designed to be used by a single thread and should not be passed around. This includes the syntactic sugar that the for-each loop provides.
What happens if I try to iterate the map with two threads at the same time?
It will work as expected...
When to use a View instead of a Table?
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Views for insertion/updates:
You can handle security issues with views by using such functionality as Oracle's "WITH CHECK OPTION" clause directly in the view
Drawbacks
You lose information about relations (primary keys, foreign keys)
It's not obvious whether you will be able to insert/updat...
HTML 5 strange img always adds 3px margin at bottom [duplicate]
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This problem is caused by the image behaving like a character of text (and so leaving a space below it where the hanging part of a "y" or "g" would go), and is solved by using the vertical-align CSS property to indicate that no such space is needed...
What does the Java assert keyword do, and when should it be used?
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Assertions (by way of the assert keyword) were added in Java 1.4. They are used to verify the correctness of an invariant in the code. They should never be triggered in production code, and are indicative of a bug or misuse of a code p...
What are the differences between “generic” types in C++ and Java?
... new foreach construct.
EDIT: the opinion above on usefulness was written by a younger self. Java's generics help with type-safety of course.
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How does a debugger work?
...gging API.
The user tells the debugger which process to attach to, either by name or by process ID. If it is a name then the debugger will look up the process ID, and initiate the debug session via a system call; under Windows this would be DebugActiveProcess.
Once attached, the debugger will ente...