for(int i=0;i&lt;=5;i++){             HtmlPage currentPage = (HtmlPage)client.getPage("http:// http://testsite.com ");             HtmlForm form = (HtmlForm) currentPage.getElementById("kelimeAraID");             HtmlButton button = (HtmlButton) form.getElementsByTagName("button").get(0);             HtmlTextInput kullaniciAdi= form.getInputByName("kelime");             kullaniciAdi.setText(arrayList.get(i));             HtmlPage sayfa2= button.click();             HtmlTableRow tr=(HtmlTableRow)sayfa2.getFirstByXPath("//*[@id=\"hor-minimalist-a\"]/tbody/tr[1]");             System.out.println(arrayList.get(i)+":"+tr.asText()); /*line:95*/             client.closeAllWindows();         }   Exception in thread "main" java.lang.NullPointerException     at htmlunit.HtmlUnit.main(HtmlUnit.java:95)
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
Dark Souls 2 coop/invading problem I was playing Dark Souls II on my pc a lot. After about 200 hours of ingame time I found that I cant summon or invade anybody. I tried new characters and reinstalling but it didn't help. So any tips, and reasons. P.S. I didn't used any cheats. Why am I getting black photos when I use the Manual feature on my DSLR? I was taking photos a few days ago, and I had it set to Manual. After about four photos, the rest started coming out black. I could see through my eyepiece clearly, and it took the photo normally, but when I reviewed it they were all black. Why not use "which"? What to use then? When looking for the path to an executable or checking what would happen if you enter a command name in a Unix shell, there's a plethora of different utilities (which, type, command, whence, where, whereis, whatis, hash, etc).  We often hear that which should be avoided. Why? What should we use instead? Will store bought chicken eggs hatch? How to change launcher icon Is there a way to customize a Lucid Lynx Launcher icon for various programs? There does not seem to be a way to do this using Create Launcher or Launcher properties. The application is not actually "installed" on the PC, the executable has just been copied. All I've been able to do so far is to add the command /home/t32/bin/pc_linux/t32marm -c /home/t32/config_usb.t32 to a generic Launcher icon using Create Launcher. Find the remainder when $45!$ is divided by $47$? Find the remainder when $45!$ is divided by $47$?  My approach I am using Wilson's theorem to solve the problem. I reduced the expression into ($47$-$1$-$1$)!/$47!$=$(47$-$1$)/$47$!-$1$/$47!$=-$1$-$1$=-$2$  Am I right in my approach.Please correct me if I am wrong? Please correct me how to approach towards the problem. .NET How to check if path is a file and not a directory? I have a path and I need to determine if it is a directory or file.    Is this the best way to determine if the path is a file?  string file = @"C:\Test\foo.txt";  bool isFile = !System.IO.Directory.Exists(file) &amp;&amp;                           System.IO.File.Exists(file);   For a directory I would reverse the logic.  string directory = @"C:\Test";  bool isDirectory = System.IO.Directory.Exists(directory) &amp;&amp;                              !System.IO.File.Exists(directory);   If both don't exists that then I won't go do either branch.  So assume they both do exists. \pause in tikzpicture breaks footline I've discovered that you can \pause within a tikzpicture, which works well until I switched the theme to one with a footline.  I've created a "test case" that illustrates the problem.  \documentclass{beamer} \providecommand\thispdfpagelabel[1]{} % Not sure what this does but our installation requires it. \usepackage{tikz} \usetheme{Madrid} % Has a footline.  \begin{document}   \begin{frame}     \frametitle{test}     \begin{tikzpicture}       \node at (0, 1) {Hello};       \pause       \node at (0, 0) {World};     \end{tikzpicture}   \end{frame} \end{document}   This creates two slides, but the footline is only drawn on the second (the headline/title appears on both). Is there anything I can do about this? The Time That 2 Masses Will Collide Due To Newtonian Gravity Performance of a Trigger vs Stored Procedure in MySQL Install packages through yum from file Is there any way to install packages through yum from a file?  Something like:   yum -f packages.txt  I couldn't find anything in the man pages.  packages.txt would contain something like:  bash bc binutils bzip2 bzip2-libs ca-certificates cairo How to get the environment variables of a subprocess after it finishes running? When I boot Ubuntu 10.04.3 from a live CD, it asks me to enter a username and password. I have not booted before, and I haven't created an account. "provide" vs. "provide with" I am wondering if the following sentence is correct:     We add the information their study provides with to our article.   The context is: their study provides with some information. And we add the information to our article.  I want to keep the word "add", and someone told me that "provides with to" sounds wired... Is there any analytics information that moderators can access for individual questions? Change the passphrase of an ecryptfs directory Suppose $f(x)$ is an irreducible polynomial over $\mathbb Z$ of degree $n$. Is it always the case that there exist distinct $x_1,\ldots,x_{2n+1}\in \mathbb Z$ such that $f(x_1),\ldots,f(x_{2n+1})$ are all prime?  So far I've tested a few irreducible polynomials using mathematica, and this has held. The motivation is to use this as a test for irreducibility, as if $f(x)$ is not irreducible then it takes on at most $2n$ prime values, as either factor takes on $1$ or $-1$ at most $2n$ times. (I'd also be interested in learning if this bound can be improved).  This could potentially be expended to other rings of integers, i.e. $\mathbb Z[i]$, but in that case the minimal number of primes needed to certify that $f(x)$ is irreducible would increase as more units appear. In which step of compilation are comments removed? What are the differences between struct and class in C++? Biblatex: nested citations with the \textcites command I'd like to type a citation within the text and another citation inside the parenthesis for the year, something like this:     The work of Author 1 (year; cited by Author 2, year)   For this, I've tried different options of the \textcite command but without results. Also I saw the solution posted , which works for multiple citations within parenthesis but not for in-text citations.  Any suggestion?