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Under what conditions is a JSESSIONID created?
...s created/sent when session is created. Session is created when your code calls request.getSession() or request.getSession(true) for the first time. If you just want to get the session, but not create it if it doesn't exist, use request.getSession(false) -- this will return you a session or null. In...
Difference between Select Unique and Select Distinct
... database brands other than Oracle, SELECT UNIQUE may not be recognized at all.
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Java String split removed empty values
...[] split = data.split("\\|", -1);
Little more details:
split(regex) internally returns result of split(regex, 0) and in documentation of this method you can find (emphasis mine)
The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resultin...
What do hjust and vjust do when making a plot using ggplot?
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I have tried that, and I get Error in grid.Call("L_textBounds", as.graphicsAnnot(x$label), x$x, x$y, : Polygon edge not found (zero-width or zero-height?) for vjust = .72 and higher.
– William Gunn
Sep 3 '11 at 0:48
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How does the socket API accept() function work?
...r IP : Server Port
So while the Server IP and Server Port are constant in all accepted connections, the client side information is what allows it to keep track of where everything is going.
Example to clarify things:
Say we have a server at 192.168.1.1:80 and two clients, 10.0.0.1 and 10.0.0.2.
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Regular expression matching a multiline block of text
...)((?:(?:\n|\r\n?).+)+)", re.MULTILINE)
BTW, you don't want to use the DOTALL modifier here; you're relying on the fact that the dot matches everything except newlines.
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Is there any way to delete local commits in Mercurial?
...y conflicts, test, and then push.
The strip command is useful when you really want to get rid of changesets that pollute the branch. In fact, if you're in this question's situation and you want to completely remove all "draft" change sets permanently, check out the top answer, which basically sugg...
ASP.NET MVC on IIS 7.5
..." in Framework64 for 64-bit Windows! that bit me in the *ss. I must've installed the 32 bit verion 4 or 5 times with no effect.
– Ben Lesh
Jan 4 '11 at 15:31
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What are '$$' used for in PL/pgSQL
...c to function definitions. It can be used to replace single quotes practically anywhere in SQL scripts.
The body of a function happens to be a string literal which has to be enclosed in single quotes. Dollar-quoting is a PostgreSQL-specific substitute for single quotes to avoid quoting issues insi...
SQL, Postgres OIDs, What are they and why are they useful?
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OIDs basically give you a built-in id for every row, contained in a system column (as opposed to a user-space column). That's handy for tables where you don't have a primary key, have duplicate rows, etc. For example, if you have a t...