Error with playing sound. java.lang.NullPointerException
What is a NullPointerException, and how do I fix it?
Am I too old for academia after a PhD? Travelling as unmarried couple in Dubai I'd wish to visit Dubai with my girlfriend, but after reading  and  I started to get a little worried about it. How should I book an hotel? Must I book two singles? Could it be a problem if we walk together in the city and go together to restaurants and malls without being married? How can I block app and game invitations once and for all in Facebook? I want to block app and game invitations once and for all in Facebook. How can I do it so they cannot disturb me anymore? What are the recommended textbooks for introductory calculus? I've already taken my calculus sequence and I'm interested in brushing up and staying sharp on the basics. So far, my calculus background is limited to single-variable calculus, which I applied in my physics sequence and engineering statistics. I learned a little bit of vector math in physics as well, but I'm not strong in it. My mathematical strengths lie in the discrete mathematics.  I'm particularly interested in studying for my IEEE Certified Software Development Associate exam - 10% of the exam is mathematics (calculus, differential equations, and statistics). Calculus is one of the mathematics knowledge areas that a software engineer should be competent in, so I'm looking for not only solidifying the courses that I've already taken, but moving forward with slightly more advanced topics, at an undergraduate mathematics level.  I'm currently using the textbook from my calculus sequence, but I'm interested to know what books other people used to learn calculus and if the book is potentially worth checking out.  What books are available to help me? How to solve the "io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information" error on Minecraft? I am getting the following error when I try to connect to a Minecraft server:  This is all servers, not just one. The error says:  io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: no further information: Version 1.12  I've tried:  Restarting Minecraft Restarting Computer Uninstalling and Reinstalling Mincraft Uninstalling and Reinstalling Java Altering Firewall Restarting Internet I've messed with my port, made a second windows account, reset netsh winsock Checked hosts Made a new WINDOWS account  The overlay in the bottom right is Geforce's Overlay for game capturing. I don't have any mods installed. A Mojang support ticket wouldn't help. Im desperate. Does $\lim_{n\to \infty} \int^{\infty}_{-\infty} f_n(x) dx\, = \int^{\infty}_{-\infty} f(x)\,dx\,$? If $\displaystyle\{f_n(x)\}$ is sequence of continuous function on $\mathbb{R}$ converging uniformly to $f(x)$, then does $\displaystyle\lim_{n\to \infty} \int^{\infty}_{-\infty} f_n(x) dx\, = \int^{\infty}_{-\infty} f(x) dx\,$ hold? I know  it holds if we integrate over an interval of the form $[a,b]$ but not sure about improper integral! Getting hyperref to work with \citeyear and \citeyearpar in biblatex Springer llncs TOC not working I can't get the TOC to work. I remember it worked before, but there was something I did (unfortunately I can't remember what it was), and after that the TOC just stopped working.  Here is a part from my document:  \documentclass[deutsch]{llncs}  \usepackage{graphicx} \usepackage[labelformat=empty]{caption} \usepackage{subcaption} \captionsetup{compatibility=false}  \bibliographystyle{unsrt}  \pagestyle{headings} \begin{document}  \sffamily  \begin{titlepage}     %Some stuff here \end{titlepage}  \thispagestyle{headings} \tableofcontents \newpage %more stuff here blablabla \section{test} \subsection{test2} \end{document} I have a very big file 4GB and when I try to read it my computer hangs. So I want to read it piece by piece and after processing each piece store the processed piece into another file and read next piece.  Is there any method to yield these pieces ?  I would love to have a lazy method. Is there a way to avoid SSH typing delay? Proof of an inequality by induction: $(1 + x_1)(1 + x_2)...(1 + x_n) \ge 1 + x_1 + x_2 + ... + x_n$ View vote count button on mobile On the mobile site, can there be a button directly below the vote up/down buttons for viewing vote counts? When I am using the mobile site and I want to view vote counts, I have to switch to the full site to do it which is very inconvenient.   It could be a small link that says "vote counts," because I don't know what the button would be (the letter "V?" a "+/-" thing? I have no idea).  Related:  , but I am requesting an additional button below the vote buttons. That way you won't accidentally click a vote button. Why wasn't Poe told about Holdo's plan? Regular cast vs. static_cast vs. dynamic_cast I've been writing C and C++ code for almost twenty years, but there's one aspect of these languages that I've never really understood. I've obviously used regular casts i.e.  MyClass *m = (MyClass *)ptr;   all over the place, but there seem to be two other types of casts, and I don't know the difference. What's the difference between the following lines of code?  MyClass *m = (MyClass *)ptr; MyClass *m = static_cast&lt;MyClass *&gt;(ptr); MyClass *m = dynamic_cast&lt;MyClass *&gt;(ptr); Passing named arguments to shell scripts Is there any easy way to pass (receive) named parameters to a shell script?  For example,   my_script -p_out '/some/path' -arg_1 '5'   And inside my_script.sh receive them as:  # I believe this notation does not work, but is there anything close to it? p_out=$ARGUMENTS['p_out'] arg1=$ARGUMENTS['arg_1']  printf "The Argument p_out is %s" "$p_out" printf "The Argument arg_1 is %s" "$arg1"   Is this possible in Bash or Zsh? It is said that we can verify time dilation by flying a very accurate clock on a fast jet or spaceship and prove that it registers less time than the clocks on earth. However, the clocks on earth would be moving relative to the clock on the spaceship, and since time always dilates and never goes faster regardless of the direction of relative motion,  the clocks on earth should register less time than the clock on the spaceship.  Is this true? Whenever there is a fast-moving object such as a rocket do all clocks on earth really become slow?  If the rocket with the clock landed after moving at relativistic speed, would its clock and the earth's clock again show the same time since during its travel both appeared slow to each other?  Or is all this just an illusion, ie. the clocks just appear to be slow to each other but in actually run at normal speed, and neither is behind when the rocket actually lands? How not to show Universal Access menu Icon in task bar in Ubuntu 18.04? Are there any infinite series about which we don't know whether it converges or not? Or are the convergence tests exhaustive, so that in the hands of a competent mathematician any series will eventually be shown to converge or diverge? EDIT: People were kind enough to point out that without imposing restrictions on the terms it's trivial to find such &quot;open problem&quot; sequences. So, to clarify, what I had in mind were sequences whose terms are composed of &quot;simple&quot; functions, the kind you would find in an introductory calculus text: exponential, factorial, etc. I have noticed that some browsers (in particular, Firefox and ) are very zealous in using cached copies of .css and .js files, even between browser sessions. This leads to a problem when you update one of these files, but the user's browser keeps on using the cached copy. What is the most elegant way of forcing the user's browser to reload the file when it has changed? Ideally, the solution would not force the browser to reload the file on every visit to the page.  I have found  and  suggestion to be useful. It turns out there is a term for this: auto-versioning. I have posted a new answer below which is a combination of my original solution and John's suggestion. Another idea that was suggested by SCdF would be to append a bogus query string to the file. (Some Python code, to automatically use the timestamp as a bogus query string, was .) However, there is some discussion as to whether or not the browser would cache a file with a query string. (Remember, we want the browser to cache the file and use it on future visits. We only want it to fetch the file again when it has changed.) \includegraphics PDF, color problem I'm using pdflatex, and use \includegraphics to include content of figures from PDF. PDF are exported from InkScape.  \begin{figure} [!h]     \centering     \includegraphics[height=3cm]{fig/SUSAN.pdf} \end{figure}   Included PDF or source SVG has same colors. Green has always RGB value (0, 255, 0). Problem occurs when I include this files from LaTeX. In output PDF on some pages colorspace is darker. Even same image on other page has different colourity.  My PDF  . As you can see on page 7 (11 in PDF) USAN areas are bright green, but then on page 5 (9 in PDF) are green points on corners more darker.