How to know that a thread is finished
How to know if other threads have finished?
How can I stop certain apps from appearing in the Dash? What is the motivation behind axiomatically forcing the underpinning group of a ring to be abelian? Noncommutative rings are vastly more complex than commutative ones, so I am assuming that allowing the additive operation to be noncommuting would just make matters worse. Is there something deeper here, or is this a restriction for the sake of convenience and simplicity? Importing users that will be installed by programs Package Listings Warning: Text dropped after begin of listing when calling function I'm trying to this:  \newcommand{\code}[1] {\begin{lstlisting} {#1} \end{lstlisting} }   But I keep getting this error:  Package Listings Warning: Text dropped after begin of listing   I'm calling \usepackage and all so, do any of you knows how to solve this? Can you maintain concentration on a spell from another plane? String vs. StringBuilder I understand the difference between String and StringBuilder (StringBuilder being mutable) but is there a large performance difference between the two?   The program I’m working on has a lot of case driven string appends (500+). Is using StringBuilder a better choice? Verbatim in beamer showing error: "File ended while scanning use of \@xverbatim." I am using Texmaker and MiKTeX on Windows 7. I have the following beamer code,  \documentclass{beamer} \theme{AnnArbor} \begin{document} \begin{frame} \begin{verbatim}     \begin{frame}[&lt;alignment&gt;]    \frametitle{Frame Title Goes Here}    Frame body text and/or LATEX code    \end{frame}  \end{verbatim} \end{frame} \end{document}   I was expecting the following output,         \begin{frame}[&lt;alignment&gt;]        \frametitle{Frame Title Goes Here}        Frame body text and/or LATEX code        \end{frame}   But instead I got the following Error Message,  File ended while scanning use of \@xverbatim.   Can any one please point out the error here. As far as I know verbatim can have anything inside it.  Also when I tried the following code,  \begin{verbatim}  \ begin{frame}[&lt;alignment&gt;]  \frametitle{Frame Title Goes Here}  Frame body text and/or LATEX code  \ end{frame} \end{verbatim}   I got the following output,      \ begin{frame}[&lt;alignment&gt;]      \frametitle{Frame Title Goes Here}      Frame body text and/or LATEX code     \ end{frame}   But I don't want space between \ and begin and \ and end. adding @2x to src above certain resolution on none retina devices Making layer or group private/hidden/invisible in Layers Panel of QGIS I have a number of layers in the Layers Panel inside a group but I don't want them shown (there's quite a lot so it looks untidy). These layers are also joined to several others. Is it possible to make these layers invisible to the user (i.e. not shown in the Layers Panel, it is not about setting the visibility of the layer) but can still be joined to other layers, or perhaps to make the group invisible? Closest I found was this post but hoping there's a more direct approach: How to make sure I'm not using any proprietary software after installation? I know I can check the currently installed non-free software with the following command (assuming aptitude is FOSS):  aptitude search '?installed (?section(restricted) | ?section(multiverse))'   And I can remove the "restricted" and "multiverse" sources (and not add any PPA's) to keep that list empty. I'm assuming from this point, whenever I apt install something, that something is either in the allowed sources or it is not found.  Is this enough? Does this make sure all software I'm running (in Ubuntu) is open-source? maximal ideal not containing some expression How to load JAR files dynamically at Runtime? After Doomsday was defeated, a spec-ops team sent to the Kryptionian ship in Metropolis found Luthor submerged in water, in front of a... thing, which "held" three metal cubes. The thing looked up, roars, and dissipates into thin air.    What the hell was that all about? I am really confused. What was that creature and what was Luthor doing with it? Array versus List: When to use which? MyClass[] array; List&lt;MyClass&gt; list;   What are the scenarios when one is preferable over the other? And why? I need to match a space character in a PHP regular expression. Anyone got any ideas?  I mean like "gavin schulz", the space in between the two words. I am using a regular expression to make sure that I only allow letters, number and a space. But I'm not sure how to find the space. This is what I have right now:  $newtag = preg_replace("/[^a-zA-Z0-9s|]/", "", $tag); I have enum and use the variables like myEnum.SomeNameA, myEnum.SomeNameB, etc.  When I return one of these variables from a function, can I print their names (such as myEnum.SomeNameA) instead of the value they returned? Continuous bijection from $(a,b) \to S^1$? Can I use a EF lens with a EF-S camera? Why is OpenJDK 10 packaged as openjdk-11-*? Are more megapixels good?  Are more megapixels bad?  Do more megapixels increase detail? Do they make my images sharper? On the other side, is there a point that is too much? Do megapixels cause increased noise and other problems? How does print and viewing size come into it?  Widespread Internet-forum wisdom used to be that 6 megapixels was the sweet spot — below that just wasn't enough, but above that, there wasn't much benefit. File sizes got larger, but detail was lost to noise and other problems. The arguments are that cramming too many pixels into a small sensor makes each pixel too small to provide any real benefit, and that higher-megapixel sensors outresolve cheap lenses anyway. (Substitute something like 12 instead of 6 if we're discussing APS-C DSLRs, or 24 for full-frame.)  By 2011,  was in the range of 12-18 megapixels. In 2016 most were are in the 16-24 megapixel range. Certainly none are at 6 anymore; even smartphones come with 8 megapixel cameras. Does this offer any real improvement over that old "sweet spot"? Has technology improved to the point where the "wisdom" needs to be updated, or are we all suffering for marketing? Or have we gone past the sweet spot in some ways, but it's okay because of previously-un-argued points. (For example: more noise, sure, but more detail as well.)  Within the 16-24 megapixel common-today range, for the same sensor size, is there any actual benefit to the higher end? How do megapixels directly affect image quality with today's technology? What are the benefits and when do they apply? What are the drawbacks, and when do they apply? How should I adjust my technique (and expectations) based on my camera's megapixel count?