Spring BindingResult Error
What causes "java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'command' available as request attribute"?
How to load JAR files dynamically at Runtime? C# How do I click a button by hitting Enter whilst textbox has focus? I'm working with a WinForm app in C#, after I type something in a textbox I want to hit the Enter key but the textbox still has focus (flashing cursor is still in textbox), how can I achieve this? I'm having an issue with the following piece of (G)AWK script:  do {     ... } while (system("sleep 10"))   My intention is to break the loop when the user presses ^C during the sleep, but it's not working.  I believe the problem is that Bash exits with 0 when interrupted with ^C, at least when it's executed by AWK's system():  $ awk 'BEGIN { print "\n" system("sleep 2") }' (let the sleep complete) 0      $ awk 'BEGIN { print "\n" system("sleep 2") }' ^C 0   Why is it so?   Is this a bug in Bash or in (G)AWK?  Is there a simple solution that doesn't involve complicated Bash-specific syntax like trap?  The best I could come up with is this:  do {     ... } while (42 == system("sleep 10 &amp;&amp; exit 42"))   which still looks like a kludge to me. Given three matrices $A$, $B$ and $C$ such that $ABA^T C$ is a square matrix, the derivative of the trace with respect to $A$ is:  $$ \nabla_A \operatorname{trace}( ABA^{T}C )  = CAB + C^T AB^T $$  There is a proof . However, I was not able to understand the second line of the proof. it says something like this:  $$ \nabla_A \operatorname{trace}( ABA^T C )= \nabla_\bullet \operatorname{trace}(f(\bullet)A^{T}C) + \nabla_\bullet \operatorname{trace}(f(A) \bullet^T C) $$  Where  $f(A) = AB$  I tried searching the proof or any hint using google, but I couldn't fine anything. Could anyone please help me with this second line. I cannot sleep. I am obsessed with this proof. Has Marvel commented on the extra Infinity Gauntlet? Way back in Thor, there was an Easter Egg Infinity Gauntlet in Odin's vault.  They even  that year to show it off.  Presently in the Marvel Cinematic Universe, they're clearly building to an Infinity Gauntlet story, and they've shown several Infinity Stones out in the universe.  The Infinity Stones are clearly not all sitting in Odin's vault, on a gauntlet.  Has Marvel commented on this issue at all in interviews?  Has the gauntlet been retconned into being some other gauntlet, or some other piece of the Infinity Gauntlet puzzle? Show that $A\in\mathbb{C}_n$ is normal $\iff$ $tr(A*A) = \sum_{i = 1}^n|\lambda_i|^2$, where $\lambda_1,...,\lambda_n$ are the eigenvalues of $A$. How do you sort a dictionary by value? I often have to sort a dictionary, consisting of keys &amp; values, by value. For example, I have a hash of words and respective frequencies, that I want to order by frequency.  There is a SortedList which is good for a single value (say frequency), that I want to map it back to the word.   orders by key, not value. Some resort to a , but is there a cleaner way? For which $f,g \in k[t]$, $k[f,g]$ is integrally closed? Let $f,g \in k[t]$, $k$ is a field of characteristic zero, $\deg(f)=n \geq 2$, $\deg(g)=m \geq 2$.     Is it possible to characterize all such $f$ and $g$ for which $k[f,g]$ is integrally closed in its field of fractions $k(f,g)$?   I do not mind to further assume that $k(f,g)=k(t)$ (but I do not want to assume that $k[f,g]=k[t]$, which makes my question trivial).  Thank you very much!  Edit: (i)  is relevant.  (ii) If also $k(f,g)=k(t)$, then being integrally closed is equivalent to $k[f,g]=k[t]$. Indeed: (a) If $k[f,g]=k[t]$ then $k[f,g]$ is integrally closed (since $k[t]$ is). (b) If $k[f,g]$ is integrally closed then, in particular, since $t \in k(t)=k(f,g)$ (= the field of fractions of $k[f,g]$) and obviously $t$ is integral over $k[f,g]$ (for example, $t$ is a root of $f(T)-f \in k[f,g][T]$) hence $t \in k[f,g]$, so $k[f,g]=k[t]$.  For example: $f(t)=t^2+1$, $g(t)=t^3-4t$. We have, $t= \frac{t(t^2-4)}{t^2+1-5}=\frac{g}{f-5}$, so $k(f,g)=k(t)$. By Abhyankar-Moh-Suzuki theorem, $k[f,g] \neq k[t]$, so $k[f,g]$ is not integrally closed. Similarly, for every $f,g$ such that $k(f,g)=k(t)$ and one of the degrees does not divides the other, then $k[f,g]$ is not integrally closed.  (iii) If also $k(f,g)=k(t)$ and $k$ is algebraically closed, then being integrally closed is equivalent to $H(t)=(f(t),g(t))$ is injective and $H'(t)=(f'(t),g'(t)) \neq (0,0)$ for every $t \in k$. Indeed, $k[f,g]=k[t]$ is equivalent to the new conditions (it is important that $k$ is algebraically closed!!).  Edit: What if we replace $k$ by an integral domain $D$ (which is a $k$-algebra)? See also  question. Any nice, stable ways to keep a window 'Always on top' on the Mac? mysql database no space available How can I get the size of a memory block allocated using malloc()? jQuery Validate Plugin - How to create a simple custom rule? Show that $\left| \frac{1}{x}-\frac{1}{z} \right| \le \left|\frac{1}{x} - \frac{1}{y} \right| + \left|\frac{1}{y} - \frac{1}{z} \right|$. I'm trying to prove that  $$ \left| \frac{1}{x}-\frac{1}{y} \right| $$  is a metric on $X = \mathbb R^+$.  The properties of non-negativity and symmetry are obvious (do I actually even need to prove them?), but the tricky one is, as usual the inequality property, i.e.  $$ d(x,z) \le d(x,y) + d(y,z) \text{ for any } z \in X. $$  So, ok, I have that  $$ d(x,z) \le d(x,y) + d(y,z) \\ \iff \left| \frac{1}{x}-\frac{1}{z} \right| \le \left|\frac{1}{x} - \frac{1}{y} \right| + \left|\frac{1}{y} - \frac{1}{z} \right| \\ \iff \left| \frac{1}{x} \right|- \left| \frac{1}{z} \right| \le \left| \frac{1}{x}-\frac{1}{z} \right| \le \left|\frac{1}{x} - \frac{1}{y} \right| + \left|\frac{1}{y} - \frac{1}{z} \right| $$  ...and that's about as far as I've gotten–which is to say, not very far. I also tried multiplying both sides by $ \left| \frac{1}{x}-\frac{1}{z} \right| $, but that wasn't very fruitful. If someone could point me in the right direction, it'd be greatly appreciated. Thanks. Does creating an object using reflection rather than calling the class constructor result in any significant performance differences? It's well seen throughout the series that there is a “curse” on the DADA teacher position, that no one can hold that post for more than a year. But it seems like Quirrell has been around for longer than a year. What's up with that? How to insert page number in Beamer navigation symbols? Are (un)tapped permanents still legal targets for "(un)tap target permanent" effects? So I noticed that many cards with tap-effects ship with a clause specifying that they can only be used on untapped permanents, such as  and .  So here's my question:   Doesn't that imply that, given the right situation, one can legally tap an already tapped permanent?   I'll give an example of the kinda scenarios this is relevant for: Can  activate her first ability when no untapped cards are around? Or, thinking untap-effects, could I bounce a forest with  even when there isn't a tapped creature available?  Notice that, unlike the previous batch of examples, the wording on these lacks the clause restricting their use to un/tapped permanents - does that mean that they aren't?  Any kind of clarification would be greatly appreciated here. TeX Live 2016: minted doesn't work with LuaLaTeX (bug fixed in June 2016) I've installed TeX Live 2016 as it was released today (thanks to the developers for that).  Now I have the following MWE:  \documentclass{article} \usepackage{minted} \begin{document}  \begin{minted}{ruby} class Foo   def init     pi = Math::PI     @var = "Pi is approx. #{pi}"   end end \end{minted}  \end{document}   When running pdflatex --shell-escape test.tex it runs through the file and produces the PDF as expected. Doing the same with lualatex --shell-escape test.tex fails with  This is LuaTeX, Version 0.95.0 (TeX Live 2016)   system commands enabled. (./test.tex LaTeX2e &lt;2016/03/31&gt; Babel &lt;3.9r&gt; and hyphenation patterns for 1 language(s) loaded. (/opt/texlive/2016/texmf-dist/tex/latex/base/article.cls Document Class: article 2014/09/29 v1.4h Standard LaTeX document class (/opt/texlive/2016/texmf-dist/tex/latex/base/size10.clo)) (/opt/texlive/2016/texmf-dist/tex/latex/minted/minted.sty (/opt/texlive/2016/texmf-dist/tex/latex/graphics/keyval.sty) (/opt/texlive/2016/texmf-dist/tex/latex/oberdiek/kvoptions.sty (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/ltxcmds.sty) (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/kvsetkeys.sty (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/infwarerr.sty) (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/etexcmds.sty (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/ifluatex.sty)))) (/opt/texlive/2016/texmf-dist/tex/latex/fancyvrb/fancyvrb.sty Style option: `fancyvrb' v2.7a, with DG/SPQR fixes, and firstline=lastline fix  &lt;2008/02/07&gt; (tvz)) (/opt/texlive/2016/texmf-dist/tex/latex/float/float.sty) (/opt/texlive/2016/texmf-dist/tex/latex/base/ifthen.sty) (/opt/texlive/2016/texmf-dist/tex/latex/tools/calc.sty) (/opt/texlive/2016/texmf-dist/tex/latex/ifplatform/ifplatform.sty (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/pdftexcmds.sty (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/ifpdf.sty) (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/luatex-loader.sty (/opt/texlive/2016/texmf-dist/scripts/oberdiek/oberdiek.luatex.lua))) (/opt/texlive/2016/texmf-dist/tex/generic/oberdiek/catchfile.sty) uname -s &gt; "test.w18"  ! Package catchfile Error: File `test.w18' not found.  See the catchfile package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.93     \CatchFileDef\@tempa{\ip@file}{}  ?    As mentioned, it's a freshly installed TeX Live 2016; I've also checked the installed Pygmentize version, which is 2.1.3 (installed via pip). Testing with TeX Live 2015, the above code, however, works without problems with both pdflatex and lualatex.  Does anybody have a hint for me on how to fix this, or is it a bug in lualatex or minted (or whatever other package) that should be reported?  Update: With minted version 2.2 (2016-06-08), the package loads the shellesc package automatically, as mentioned by @David Carlisle and @egreg in the comments; therefore, the problem should not occur any more, if you have this version installed. In Illustrator is there a way to precisely scale to a pivot point or "reference point" that is off the screen? I mean when you want to zoom in somewhere far away from where you set that point and then scale precisely to align something.   Here's :     To scale relative to a different reference point , click where you   want the reference point to be in the document window, move the   pointer away from the reference point, and then drag until the object   is the desired size.   Well, I tried using this click-drag scaling method as well, but the level of precision is too low to be usable. It overshoots or undershoots the guide I'm aiming for.  The Scale tool's pop-up dialog isn't useful either. It only offers percentages. And moving/zooming are disabled while the dialog window is up, meaning I cannot navigate to the guide I need to see.  For these reasons, I need to be zoomed in on the guide, tweaking the measurements from the top Control Panel.  Some images to help illustrate what I mean:    ▲ The circle marks where I would like the center of my scale transformation to be.    ▲ Now zoomed in somewhere else, I am trying to get the black border of this bitmap image to align perfectly with the vector guide by scaling it.    ▲ I nudge the numbers in the Control Panel until the image is perfectly aligned.  One would think all would be perfect, but then I look and my reference point has vanished!   It seems the scaling has been executed relative to one of these limited nine reference point choices  instead of the reference point I specified.  There must be a way to scale precisely to a specific reference point in illustrator. Can somebody please enlighten me? Error reading from file: Input/output error