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What's the difference between ConcurrentHashMap and Collections.synchronizedMap(Map)?
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Please also note that the ConcurrentHashMap does not allow null keys or values. So they are NOT equal alternatives of a synchronized map.
– onejigtwojig
Oct 20 '11 at 19:42
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How can I match a string with a regex in Bash?
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FWIW, the syntax for negation (i.e. does not match) is [[ ! foo =~ bar ]].
– Skippy le Grand Gourou
Jan 2 '17 at 15:56
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Force IE compatibility mode off using tags
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I have found that this does NOT work if the user (or the sysadmin) has turned on compatibility mode as a default by going to Tools->Compatibility View Settings, and checking Display all websites in Compatibility View. To fix the problem, I have...
How to calculate a logistic sigmoid function in Python?
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This does not work for extreme negative values of x. I was using this unfortunate implementation until I noticed it was creating NaNs.
– Neil G
Apr 25 '15 at 10:22
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How can I clear scrollback buffer in Tmux?
...he tmux command prefix (ctrl-b by default). I use bash, so ctrl-l already does the equivalent of typing "clear" at the command line. With these two keys I get a nice ctrl-l, ctrl-k combo, which moves all the scroll buffer off the screen (the "clear") and then deletes all that history (the tmux "cl...
Hide scroll bar, but while still being able to scroll
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This solution does not work when the content's width is set to auto. when scrolling all the way to the right, part of the content is still not visible. Why is that? Any solutions? Checkout the problem here : jsfiddle.net/50fam5g9/7 Note : ...
How do I detect that an iOS app is running on a jailbroken phone?
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Where does apt store its info? Or could I just call a system() command and find out. I want to find out if they have certain apps, and if they have them, then restrict the app
– conradev
Mar 6...
What is a daemon thread in Java?
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A daemon thread is a thread that does not prevent the JVM from exiting when the program finishes but the thread is still running. An example for a daemon thread is the garbage collection.
You can use the setDaemon(boolean) method to change the Thread daemon...
What is the difference between “INNER JOIN” and “OUTER JOIN”?
...f A and B, i.e. all the rows in A and all the rows in B. If something in A doesn't have a corresponding datum in B, then the B portion is null, and vice versa.
select * from a FULL OUTER JOIN b on a.a = b.b;
a | b
-----+-----
1 | null
2 | null
3 | 3
4 | 4
null | 6
null | ...
SQLAlchemy: What's the difference between flush() and commit()?
...he session object registers transaction operations with session.add(), but doesn't yet communicate them to the database until session.flush() is called.
session.flush() communicates a series of operations to the database (insert, update, delete). The database maintains them as pending operations i...