Facing "nullpointer exception" in appium
What is a NullPointerException, and how do I fix it?
Invalid Topology [Topoengine error] from ArcGIS for Desktop? Using ArcGIS 10.1 for Desktop, I'm trying to run the Identity function on two large data sets but it fails every time. I don't think it is a lack of hardware as I can run other processes on the same data sets.   I've already updated software, and added the 64 bit geoprocessing add-in, checked and repaired geometry, and done the fix in  (set ARCTMPDIR env variable to a writable local folder).   Executing: Identity DudleyStamp OA2011 "D:\Case Studies\National2\National.gdb\DudleyStampOA11" ALL "1 Meters" NO_RELATIONSHIPS  Start Time: Wed May 08 21:11:43 2013 Reading Features... Processing Tiles... Assembling Tile Features... ERROR 999999: Error executing function. The table was not found. The table was not found. [DudleyStampOA11] The table was not found.   The table was not found. [DudleyStampOA11]   Invalid Topology [Topoengine error.] Failed to execute (Identity). Failed at Wed May 08 21:45:41 2013 (Elapsed Time: 33 minutes 58 seconds)   Based on comments so far I tried copying data to new file geodatabase, and running the tool from ArcCatalog still get exactly the same error.  I have ordered 16GB of the fastest RAM my computer can take (I current have 4GB). I also have a 6 Core AMD Phenom II X6 1090T, SSD, and AMD Radeon HD 6970 Graphics Card. So I'm not sure what more hardware I can add.  I've also tried increasing the size of the page file which was a suggestion I found on Google with no effect. Proof of matrix norm property: submultiplicativity Cannot open adobe reader on Ubuntu 12.10 64bits What's the difference between Google Chrome and/or Chromium? What are the advantages/disadvantages to each? I used Google Chrome in Windows, and am now using Chromium in Ubuntu.  Is there any difference to the two programs?  What are the advantages and disadvantages to each program?  Which one seems better? is a simple way to script small GUIs.  Can anyone give a nice example with a button and a text widget. When the button is pressed should a shell command be executed and the output piped to the text widget.  If you have other nice and clean examples for useful tasks, please add them too. How do we get Community Promotion Ads on beta sites? All the launched sites get Community Promotion Ads meta posts posted every year by a SE mod.  Previously, I thought that beta sites simply weren't allowed them. However,  is still in beta, and they had community promotions meta posts in  and  (I guess they haven't made one for 2015 yet).  So what happens? Do you just have to ask for one? Can the moderators of that site just create one as they like? Can anyone on that site just create one as they like? I searched all over this site and the web for a good and simple example of autocomplete using jQuery and ASP.NET. I wanted to expose the data used by autocomplete with a webservice (and will probably do that next). In the meantime, I got this working, but it seems a little hacky...  In my page I have a text box:  &lt;input id="txtSearch" type="text" /&gt;   I am using jQuery autocomplete, set up per their example:  &lt;link rel="stylesheet" href="js/jquery.autocomplete.css" type="text/css" /&gt; &lt;script type="text/javascript" src="js/jquery.bgiframe.js"&gt;&lt;/script&gt; &lt;script type="text/javascript" src="js/jquery.dimensions.pack.js"&gt;&lt;/script&gt; &lt;script type="text/javascript" src="js/jquery.autocomplete.js"&gt;&lt;/script&gt;   Here is where it starts to get hacky... I call a page instead of a webservice:    &lt;script type="text/javascript"&gt;     $(document).ready(function(){         $("#txtSearch").autocomplete('autocompletetagdata.aspx');     });         &lt;/script&gt;   In the page I stripped out ALL of the html and just have this (otherwise, various HTML bits show up in the autocomplete dropdown):  &lt;%@ Page Language="C#" AutoEventWireup="true" CodeFile="autocompletetagdata.aspx.cs" Inherits="autocompletetagdata" %&gt;   And in my autocompletetagdata.aspx, I am using SubSonic to query, format and return data from the database (one data item per line):  protected void Page_Load(object sender, EventArgs e) {     // Note the query strings passed by jquery autocomplete:     //QueryString: {q=a&amp;limit=150&amp;timestamp=1227198175320}      LookupTagCollection tags = Select.AllColumnsFrom&lt;LookupTag&gt;()         .Top(Request.QueryString["limit"])         .Where(LookupTag.Columns.TagDescription).Like(Request.QueryString["q"] + "%")         .OrderAsc(LookupTag.Columns.TagDescription)         .ExecuteAsCollection&lt;LookupTagCollection&gt;();      StringBuilder sb = new StringBuilder();      foreach (LookupTag tag in tags)     {         sb.Append(tag.TagDescription).Append("\n");     }      Response.Write(sb.ToString()); }   If you don't do a LIKE query, then it returns everything that contains a match for the character(s) you type -- e.g., typing "a" will include "Ask" and "Answer" as well as "March" and "Mega." I just wanted it to do a starts with match.  Anyway, it works and it's pretty easy to set up, but is there a better way? This is an unproven proposition I've come across in multiple places.   Suppose $A$ is a commutative Noetherian ring, and $S$ a multiplicative subset of $A$. Then $S^{-1}A$ is Noetherian.  Why is this? I thought about taking some chain of submodules $$ S^{-1}M_1\subset S^{-1}M_2\subset\cdots $$ and pulling back to a chain  $$ M_1\subset M_2\subset\cdots $$ of submodules of $A$ which must eventually stablize. Is there more to it than this? I kind of wary of assuming all submodules of $S^{-1}A$ have form $S^{-1}M$ for $M\leq A$. Unity doesn't load, no Launcher, no Dash appears When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing. java.lang.StringIndexOutOfBoundsException: String index out of range Is Meta Stack Overflow just the meta for Stack Overflow or is it a somewhat special meta site? Initially I thought that Meta Stack Overflow was the common meta for all SE sites.   Then I noted that  has its own meta site.   It took a while for me to learn that even Server Fault has its own meta site.  Looking at my reputation points, I see difference between Stack Overflow and Meta Stack Overflow, but not between the other sites and there corresponding meta sites.  Now, is Meta Stack Overflow in some sense the master meta site of all or not? How to fix Finance::Quote to pull quotes in GnuCash I made the jump from Jumsoft's Money app to GnuCash a while back. It appealed to all my OCD tendencies. I don't know how to use Perl, or stuff of the sort, but with detailed instructions I manage to get things done... when I can find them.  I set up Finance::Quote to pull quotes after I set up GnuCash. I even managed to get it to pull quotes for Korean funds. And every thing had been working well, until tonight. I only get back a pop-up that states "There was an unknown error while retrieving the price quotes." That's where I need help. What can I do?  I dug around and found that it seems that it has something to do with Yahoo Finance ending it's API support. I also learned that Finance::Quote can pull data from many sources, so I don't really understand why one missing API would break it. I also saw that someone out there is trying to use AEX to pull the quotes instead for GnuCash specifically. I found Finance::Quote on cpan (I also first heard of cpan), but I don't understand what I'm looking at. But that's all beside the point. I don't know how to fix this.  Any help would be appreciated. I'm on Windows 10, GnuCash version 2.6.17, and have Strawberry Perl 5.18.2.2-32bit installed.  edit Thanks everyone who responded. It seems to be working more or less. The currency and Korean funds still haven't updated, but you've shown this horse to water. I'll do my best to drink it now. Does non-mass-energy generate a gravitational field? At a very basic level I know that gravity isn't generated by mass but rather the  and when I wave my hands a lot it seems like that implies that energy in $E^2 = (pc)^2 + (mc^2)^2$ is the source of gravity.  If the total energy of a particle contributes to the generation of a gravitational field, that seems to imply some strange things.  For example, you could accelerate a particle like an electron to such a high velocity that it has enough momentum / kinetic energy to collapse into a black hole.  An observer traveling with the electron would see an electron and stationary observers would see an arbitrarily massive black hole flying by.  These observations seem to be contradictory.  The same would be true of an extremely high energy photon.  Another consequence is that a stationary particle could appear to have so much mass that it could attract / deflect the trajectory of a rapidly moving observer.  It seems odd that at low velocities you wouldn't even notice a stationary electron as you pass it by but at high velocities the gravitational field you observe could be significant enough to alter your path.  Am I correct that non-mass-energy generates a gravitational field?  If it does, how are these strange observations like a particle looking like a black hole in one reference frame but not another reconciled? Inverse metric in linearised gravity How to make different materials for different objects? When I change one material, it changes it on another object. Why and how do I fix it? is there some link between the objects?    Here is my blender file of Iron Man's faceplate.  Here is my whole screen with the main portion of the face selected. On the right, you can see the material, and I can tell you that that is the same as the eyes part: How to re-download Lion to create a VMWare Fusion 4 virtual machine? I have a MacBook with Lion installed.  I bought VMWare Fusion 4 because I want to create a Lion VM.  As far as I can tell I need to point VMWare to the Lion installer that is downloaded from the App Store, but that file deleted itself after Lion was installed.  How do I re-download the Lion installer (and keep it around) to create a VMWare Fusion 4 virtual machine? Is there an efficient method of converting an integer into the written numbers, for example:  string Written = IntegerToWritten(21);   would return "Twenty One".  Is there any way of doing this that doesn't involve a massive look-up table? How do I merge two dictionaries in a single expression (taking union of dictionaries)? Draw a vertical line over the entries of a column in an array I'd like to draw vertical/horizontal lines over the entries of a column/row in an array. I find the method to draw horizontal lines at . But when I used the same way to draw the vertical lines. It didn't look well. My codes are:  \usepackage{tikz} \usetikzlibrary{calc} \newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};} \newcommand{\DrawLine}[3][]{% \begin{tikzpicture}[overlay,remember picture]     \draw [#1] ($(#2)+(0,0.6ex)$) -- ($(#3)+(0,0.6ex)$); \end{tikzpicture}% }%  \begin{displaymath} \left[ \begin{array}{cccc} \tikzmark{11}{15} &amp; 0 &amp; \tikzmark{13}{0} &amp;0\tikzmark{14} \\ 0 &amp; 50 &amp; 20 &amp; 25 \\ 35 &amp; 5 &amp; 0 &amp; 10\\ \tikzmark{41}{0} &amp; 65 &amp; \tikzmark{43}{50} &amp; 65 \end{array} \right]. \DrawLine[black,thick]{11}{14} \DrawLine[black,thick]{11}{41} \DrawLine[black,thick]{13}{43} \end{displaymath}   The result looks like     But the result I want is     Does anyone know how to fix this? Thank you. In other words, why do we need to connect the battery positive to the negative to get electron flow? As far as I know, voltage difference is what drives current flow.  From what I understand, there's a surplus of negative charge (electrons) in the positive end of a battery (weird I know, but I guess they do it for mathematical reasons). Between the positive and negative ends of the battery is some kind of wall that prevents the electrons from diffusing, so they have to go the long way (through a wire to the other end of the battery) to diffuse and reach the receiver atoms/molecules.  So why not just have the surplus of electrons on one end go to ground to equalize (e.g. 5 volts to 0 volts should produce current)? Why does it have to be the other end of the battery? I'm sure there's atoms/molecules in the ground that could accept the extra electrons (receivers atoms/molecules for the donors in the battery).