I've been trying to instantiate a XSSFWorkbook using a FileInputStream, based on an existing excel file (xlsx). I should use an Excel template due to some business requirements. XSSFWorkbook templateWorkbook = new XSSFWorkbook(new FileInputStream(&quot;myTemplate.xlsx&quot;)); I'm using XSSF because I want to improve the performance while creating large Excel files (~50k rows). So I've followed some examples like  that shows how to use SXSSF to increase performance. Then, after get the Excel template into a new XSSFWorkbook I do this: SXSSFWorkbook mySXSSFWorkbookFromTemplate = new SXSSFWorkbook(templateWorkbook, 100); However, I always get either the following exception (while reading the Excel file, I mean I don't even get into the SXSSFWorkbook instantiation):  java.lang.NoClassDefFoundError: org/apache/xmlbeans/impl/store/DomImpl$CdataNode  or this one:  java.lang.NoClassDefFoundError: org/apache/xmlbeans/xml/stream/XMLStreamException  I'm able to solve the last exception while re-running/re-debugging the unit test (which is weird because the code and the POM dependencies remain exactly the same). So now, I'm stuck getting the NoClassDefFoundError DomImpl$CdataNode This is how my POM file looks like.     &lt;dependency&gt;         &lt;groupId&gt;org.apache.poi&lt;/groupId&gt;         &lt;artifactId&gt;poi&lt;/artifactId&gt;         &lt;version&gt;5.0.0&lt;/version&gt;     &lt;/dependency&gt;      &lt;dependency&gt;         &lt;groupId&gt;org.apache.poi&lt;/groupId&gt;         &lt;artifactId&gt;poi-ooxml&lt;/artifactId&gt;         &lt;version&gt;5.0.0&lt;/version&gt;     &lt;/dependency&gt;      &lt;dependency&gt;         &lt;groupId&gt;javax.xml.stream&lt;/groupId&gt;         &lt;artifactId&gt;stax-api&lt;/artifactId&gt;         &lt;version&gt;1.0-2&lt;/version&gt;     &lt;/dependency&gt;      &lt;dependency&gt;         &lt;groupId&gt;org.apache.xmlbeans&lt;/groupId&gt;         &lt;artifactId&gt;xmlbeans&lt;/artifactId&gt;         &lt;version&gt;4.0.0&lt;/version&gt;     &lt;/dependency&gt;  UPDATE: I'm able to see the CdataNode.java class withing the xmlbeans jar file.
I am getting a NoClassDefFoundError when I run my Java application.  What is typically the cause of this?
LaTeX baffled by BOM---Unicode's byte order mark. Unicode applies the convention of using a  as signature at the beginning of a text stream, identifying the encoding used within it. The following three bytes at the beginning of a file: EF BB BF, identifies this file as a UTF8 file. Vi and most text editors gracefully ignore this signature. Open office does that as well, but it adds this signature at the beginning.  Now, if I open a TeX file with OpenOffic.org, and I do that quite a lot (for mixed directionality editing), the signature is added, and baffles LaTeX, which produces an error message such as:   ! LaTeX Error: Missing \begin{document}.   See the LaTeX manual or LaTeX Companion for explanation.  Type  H &lt;return&gt;  for immediate help.  ...                                                l.1   ��\documentclass{article}   whereas a simple dump of the file does not show the problem. Is there a way to eliminate this problem, while staying in the realm of latex? Why does do-release-upgrade on Xubuntu running version 18.04 not offer to update to 20.04.1? I've understood that when I run the Software Updater GUI program, or when I execute do-release-upgrade on the command line, it should offer to upgrade to the latest LTS release if (1) I've got the release update behaviour set to lts, and (2) if the first point release of a newer LTS release is available. I have a couple of machines running the Xubuntu LTS release 18.04. The contents of file etc/update-manager/release-upgrades on all these machines is [DEFAULT] Prompt=lts  That satisfies condition (1). Also, it seems that Xubuntu 20.04.1 is already released, satisfying condition (2). However, neither do-release-upgrade nor the Software Updater offers to upgrade to that release. Why? Edited to add: It seems this question is a duplicate of . A book about explorers stranded on a planet with two computers I have been looking for a book that I read in the 80's but it's probably older. It was about a spaceship from Earth in a very long mission to discover life? I don't remember, but they had been far too long in space without any results, so the crew was on the verge of mutiny.  They land on a planet, home of two super-computers called...? Alpha? Beta? One seemed more advanced than the other, the planet was void of any other life, and supposedly it was forseen that the planet would be struck by a comet, and the computers see the ship as a way to save or abandon the planet before the impact.  At some point one member of the crew is captured by the computers, and it's vivisected in an attempt to get data about humans. Then they "reassemble" the crew member before returning it to the ship, hoping that the humans could "reactivate it" since the computers were unable to do so. Which of course enrages the ship's crew.  The ship was unable to take off for reason that I don't remember and they must fight the computers to save themselves.  Does anyone know what this is?  Thanks, as soon as I read the names, they did ring a bell on my memory. The case it's closed then. Is the converse of Cayley-Hamilton Theorem true? The question is motivated from the following problem:     Let $I\neq A\neq -I$, where $I$ is the identity matrix and $A$ is a real $2\times 2$ matrix. If $A=A^{-1}$, then the trace of $A$ is   $$ (A) 2 \quad(B)1 \quad(C)0 \quad (D)-1 \quad (E)-2$$   Since $A=A^{-1}$, $A^2=I$. If the converse of  is true, then $\lambda^2=1$ and thus $\lambda=\pm1$. And then $\rm{trace}(A)=1+(-1)=0$.   Here are my questions:   Is  $C$ the answer to the quoted problem?  Is the converse of Cayley-Hamilton Theorem, i.e.,"for the square real matrix $A$, if $p(A)=0$, then $p(\lambda)$ is the characteristic polynomial of the matrix $A$" true? If it is not, then what's the right method to solve the problem above? This is a question that arose in the comments here:   I normally hide footnotes from the TOC by doing this:  \section[title]{title\footnote{This is a footnote.}}.   This works in a lot of document classes (memoir, article, ...), but not in all of them. amsbook, for example, uses the optional argument only for the running heads so the footnote mark still ends up in the TOC. So what is the 'universal solution'? Find conditional expectation from a 3-dimensional random vector? If a ring element is right-invertible, but not left-invertible, then it has infinitely many right-inverses. Let $A$ be a ring and $a\in A$ an element that has a right-inverse but does not have a left-inverse. Show that $a$ has infinitely many right-inverses. I just installed Dufour on my Windows 7 Lenovo ThinkCentre desktop. When I open 2.0.1 I get this error window:    And when I try to add the 'Add Delimited Text Layer' plugin I get this message:    When I click 'OK' the program closes.   Any help is greatly appreciated - thanks. Don't worry, I have written your name on the attendance sheet.   Or     Don't worry, I wrote your name on the attendance sheet. Does the equivalence $$\neg\neg (P \rightarrow Q) \leftrightarrow (\neg\neg P \rightarrow \neg\neg Q)$$ hold in propositional intuitionistic logic? In propositional classical logic the equivalence holds obviously since $P \leftrightarrow \neg\neg P$. However, the similar-looking implication $\neg\neg (P \vee Q) \rightarrow (\neg\neg P \vee \neg\neg Q)$ is . The validity of the backward implication comes up in  as well. Accidentally moved directories under root Using oscilloscope safely with AC mains I know there is quite few discussions already on this topic, but since English isn't my first language, I though it better to get some more information about this.  I have used oscilloscopes to troubleshoot electronics problems and measure AC engine current spikes at startup, but I have no experience using them to measure high voltage levels and my experience is with old analog scopes.  So now I have this new DSO and the input rating is 400V peak to peak AC, so it can handle about 140V AC RMS? Not that I'm going to input that much there.  Since I live in Europe the mains here are 230 V @ 50 Hz I can't measure them directly.  If I set the attenuation from the scope and probe to 10X, the voltage is 23 RMS and it is safe to measure? And yes the probes are rated for 1kV.  If that is true, it's also safe to measure voltage between two main lines (400V RMS), since the peak-to-peak would be about 112 volts?  SAFETY: When I am measuring AC, I will be using the scope from its internal battery or with a isolating transformer (1:1) so that it is floating, meaning that there is no connection to earth ground. Are there any other safety issues I have not realized? Suppose $\mu(X)&lt;\infty$. Show that if $\ f\in\ L^q(X,\mu)$ for some $1\le q&lt;\infty$ then $\ f\in\ L^r(X,\mu)$ for $1\le r&lt;q$   In the solution the assistant wrote this:  If $1\le r&lt;q$ then $q/r\ge 1$. Let p be the dual exponent to $q/r$ (i.e. $\frac{1}{q/r}+\frac{1}{p}=1)$  then by Hölder Inequality  $\int_{X}|f|^rd\mu\le\underbrace{(\int_{X}|f|^qd\mu)^{r/q}}_{??????}(\int_X1^pd\mu)^{1/p}&lt;\infty$  for me the middle part doesn't make sense (it is not the hölder inequality) can somebody show it ?  instead of this can't we say (only in this case) that   $\int_{X}|f|^rd\mu\le (\int_{X}|f|d\mu)^r$ then  $(\int_{X}|f|d\mu)^r\le ((\int_{X}|f|^qd\mu)^{1/q}(\int_X1^pd\mu)^{1/p})^r&lt;\infty$  ? Show that    $$\frac{\sum_{i=0}^n\binom{k}{i}\binom{M-k}{n-i}\frac{k-i}{M-n}}{\binom{M}{n}}=\frac{k}{M},$$ where $M-k&gt;n$ and $k&gt;n$   From Vandermonde's identity, I get $\sum_{i=0}^n\binom{k}{i}\binom{M-k}{n-i}=\binom{M}{n}$.   But what about the sum of the product in the numerator? Any hint will be helpful. Simple UV Mesh Unwrapping Scale issue I'm having problems using the UV mapping in blender 2.67. Specifically, I am trying to unwrap a really simple mesh, but the UV map is still giving me a net where some of the boxes are completely out of proportion to the others, which causes the texture to stretch horribly. Here is a picture to illustrate:    The mesh only has those three faces you can see in the picture, and the single seam on the front corner. It's a trivially simple mesh, so I really don't understand why the two side faces are being stretched in the UV map to be the same size as the top face. I've tried clicking the average islands scale button as suggested by some of the answers to other questions but that has no effect. It's frustrating because it seems so simple.  Hopefully someone can show me the presumably simple mistake I am making!  Edit: Just to make this clearer, I have already added a seam as the first answer suggests i do. Hopefully this picture will make that clearer, the yellow arrow is pointing to the edge i seamed. The mesh is only three faces so should only need this single seam. The image shows the mesh from infront and behind/underneath so it should make more sense.    Double Edit: One more picture for clarity on the seam issue. The mesh is unfolding correctly, it is just the scale of the unfolded map that is incorrect (in relation to one another) Recently, I have noticed that on most applications I have on Ubuntu 16.04, when I load the application, the window is displayed with a strange multi-coloured border (see the images below). If I maximise the window though, the border disappears and the window is displayed as expected.  This started happening for no apparent reason. If I reboot my machine, things return to normal at first, but after a while the problem comes back.  The issue occurs on most applications, including Nautilus, Software Centre, Terminal, System Settings, etc... I also get the same border appearing when I right click on the desktop, with the border surrounding the pop-up menu.  However, I have noticed that it does not happen on Chrome, but it does happen on other applications which did not come with Ubuntu by default.  Any ideas on what is causing the problem? Thanks! Joda Time: How to get dates of weekdays on some date interval? What is the danger of running untrusted software as a normal user Sometimes I have to use some propriety softwares which I don't trust or even pre-compiled open source ones which I don't know if they've been compiled as their source are.   Lets say we installed a propriety application in /opt/software, then we run it as a normal user (without sudo, gksudo, etc).   I know when we run a program it is able to connect to the Internet, monitor X, keystrokes, collect user data and so on. It can't change anything important in the system or infect the system, (because of the Linux permissions system). It is possible for program to add some plug-in/extension to a user's browser (Because browser profiles are available in user home directory). After closing the program and rebooting it can't do anything anymore. Wrong because:   Program can add itself to a shell/file/directory which does the autostart process, so it will run at any login.  If we consider the autostart process clean, without rebooting there is a chance that a process of the program is still active. Programs can delete or modify any file in the user home directory (or any other file which a user has write permission to).   So what should we do?   I think the only safe way to run a propriety program is running it as another user. If running the program as another user somehow is not possible then we should change the autostart files permission so only root can change them. then after closing the program a reboot will do the job.   Am I right? Is there anything that I'm missing? Remotely run script on Unix, get output locally? I need to run a (Tcl, or whatever) script on a remote Unix machine, from a (local) Windows command shell, and I want the stdout/stderr of the script to show up in the Windows CLI. The exit code would also be useful.  Is this possible using ssh (putty)? Or by any other means?  Thanks! I have started a long process through a terminal. Is it possible to make the Ubuntu terminal make a sound once the process is complete? This way, I don’t need to keep checking, but will instead be notified through a sound.