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Why can outer Java classes access inner class private members?
...he inner class is just a way to cleanly separate some functionality that really belongs to the original outer class. They are intended to be used when you have 2 requirements:
Some piece of functionality in your outer class would be most clear if it was implemented in a separate class.
Even thoug...
What's the difference between ConcurrentHashMap and Collections.synchronizedMap(Map)?
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For your needs, use ConcurrentHashMap. It allows concurrent modification of the Map from several threads without the need to block them. Collections.synchronizedMap(map) creates a blocking Map which will degrade performance, albeit ensure consistency (if used properl...
knitr Markdown highlighting in Emacs?
...r the former you need polymode and for the latter markdown.el. Besides, if all you want is to just switch the ESS engine from Sweave to knitr (without highlighting!), there is no need to go through all the complication of this article, just add (setq ess-swv-processor 'knitr) in you init file.
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javax.faces.application.ViewExpiredException: View could not be restored
...ession cookie is not maintained anymore for some reason in browser, or by calling HttpSession#invalidate() in server, or due a server specific bug with session cookies as known in WildFly), then the serialized view state is not available anymore in the session and the enduser will get this exception...
Is embedding background image data into CSS as Base64 good or bad practice?
... without any of the style information until the download completes. For small images that you don't intend on changing often if ever it is a fine solution.
as far as generating the base64 encoding:
http://b64.io/
http://www.motobit.com/util/base64-decoder-encoder.asp (upload)
http://www.greywyve...
How can I reset or revert a file to a specific revision?
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@aliteralmind: Actually, yes, there's a way to do it: "git log --reverse -1 --ancestry-path yourgitrev..master" and then use the appropriate options to just get the git rev. --ancestry-path will "draw a line" between two commits and -1 will sho...
How can I find out the total physical memory (RAM) of my linux box suitable to be parsed by a shell
...d this recently, and have a simple command to get the total memory size of all memory modules on a system: dmidecode -t 17 | grep "Size.*MB" | awk '{s+=$2} END {print s / 1024}'
– Jonesinator
Jun 18 '14 at 23:53
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How can I develop for iPhone using a Windows development machine?
...the old Dell Precision I had at the time :)
There are three routes;
Install OSx86 (aka iATKOS / Kalyway) on a second partition/disk and dual boot.
Run Mac OS X Server under VMWare (Mac OS X 10.7 (Lion) onwards, read the update below).
Use Delphi XE4 and the macincloud service. This is a commercia...
how to check the dtype of a column in python pandas
...ions to treat numeric columns and string columns. What I am doing now is really dumb:
6 Answers
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What's the fastest way to merge/join data.frames in R?
...(y) from main.d group by g1, g2"))
)
The outputs from the two benchmark call comparing the merge calculations are:
Joining by: x
test replications elapsed relative user.self sys.self user.child sys.child
3 data.table 1 0.34 1.000000 0.31 0.01 NA NA
2 ...