I have a problem with my face recognition code. Everytime I run the code there will be error of :  Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - cannot find symbol symbol:   variable AppearanceRecognition location: class AppearanceRecognition.EigenFacesRunner at AppearanceRecognition.EigenFacesRunner.main(EigenFacesRunner.java:42) C:\Users\Adila\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1 BUILD FAILED (total time: 0 seconds)   I copy this code from somewhere but I didn't remember where so I find it very difficult for me to understand the code.  The code is:     package AppearanceRecognition;  import java.net.URISyntaxException;   public class EigenFacesRunner {   private AppearanceRecognition.Visualizer visualizer; private FaceFinder faceFinder; EigenFacesRunner() throws URISyntaxException {     FaceFinder faceFinder = new FaceFinder();     Visualizer visualizer = new Visualizer(faceFinder);     //visualizer.setOkHandler(new AppearanceRecognition.OkHandler(visualizer, faceFinder)); }  //    public static int exponent(int base, int power) { //        int ans = -1; //        if (power &gt;= 0) { //            ans = 1; //            for (int i = 0; i &lt; power; i++){ //                ans *= base; //            } //        } // //        return ans; //    } //  //    public static int exponentRec(int base, int power) { //        if (power == 0) //            return 1; // //        return  base * exponentRec(base, power - 1); //    }  public static void main(String [] args) throws URISyntaxException {     int power = 0;     int base = 3;     //System.out.println(base + "^" + power + " equals " + exponent(base, power));     //System.out.println(base + "^" + power + " equals " + exponentRec(base, power));      AppearanceRecognition.Visualizer visualizer = new AppearanceRecognition.Visualizer();     FaceFinder faceFinder = new FaceFinder();     EigenFacesRunner runner = new EigenFacesRunner();  }    public static void debug(String msg){         System.out.println(msg);     } }
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?
I am trying to use a  as input and then creating a query with it - so I need a .    I was surprised to find that it couldn't do the conversion implicitly or explicitly - but I don't even know how I would do this, as the Java API is still fairly new to me. Eclipse: How to build an executable jar with external jar? I am trying to build an executable jar program which depends on external jar downloaded. In my project, I included them in the build path and can be run and debug within eclipse.  When I tried to export it to a jar, I can run the program but I can't when I try to press a button which includes function calls and classes from the external jar. I have edited the environment variables (Windows XP) CLASSPATH to include paths of all the external jar, but it doesn't work.  A point to note is that I got compile warnings while exporting my executable jar, but it doesn't show up any description about the warnings.  Would someone kindly provide a thorough guide on how to include an external jar program using eclipse? Suppose I wish to allow only users who have scored at least 15 in the particular tag to answer my question, Is it possible to set a condition like this while asking a question? So that I can avoid strangers/answers from dummy users. Run a command that is shadowed by an alias Let's say I have the following alias in bash - alias ls='ls --color=auto' - and I want to call ordinary ls without options. Is the only way to do that is to unalias, do the command and then alias again? Or there is some nifty trick or workaround? How to handle ordinal categorical variable as independent variable I am using a logit model. My dependent variable is binary. However I have an independent variable which is categorical and contains the responses: 1.very good, 2.good, 3.average, 4.poor and 5.very poor. So, it is ordinal ("quantitative categorical"). I am not sure how to handle this in the model. I am using gretl.  [Note from @ttnphns: Although the question says the model is logit (because the dependent is categorical), the crucial issue - ordinal independent variables - is basically alike, be the dependent categorical or quantitative. Therefore the question is equally relevant to, say, linear regression too - as it is to logistic regression or other logit model.] Windows 10: How to change a theme slideshow time interval? It's all int the title; I find myself unable to set a precise time interval defining how often the background pictures of the theme I am currently using change.  The only similar option available in Windows 10 settings applies only to single background images and not to multiple background images included in a theme.  Thanks in advance,  N. I would like to know how I can get the value of a node with the following paths:   config/global/resources/default_setup/connection/host config/global/resources/default_setup/connection/username config/global/resources/default_setup/connection/password config/global/resources/default_setup/connection/dbname   from the following XML:  &lt;?xml version="1.0"?&gt; &lt;config&gt;     &lt;global&gt;         &lt;install&gt;             &lt;date&gt;&lt;![CDATA[Tue, 11 Dec 2012 12:31:25 +0000]]&gt;&lt;/date&gt;         &lt;/install&gt;         &lt;crypt&gt;             &lt;key&gt;&lt;![CDATA[70e75d7969b900b696785f2f81ecb430]]&gt;&lt;/key&gt;         &lt;/crypt&gt;         &lt;disable_local_modules&gt;false&lt;/disable_local_modules&gt;         &lt;resources&gt;             &lt;db&gt;                 &lt;table_prefix&gt;&lt;![CDATA[]]&gt;&lt;/table_prefix&gt;             &lt;/db&gt;             &lt;default_setup&gt;                 &lt;connection&gt;                     &lt;host&gt;&lt;![CDATA[localhost]]&gt;&lt;/host&gt;                     &lt;username&gt;&lt;![CDATA[root]]&gt;&lt;/username&gt;                     &lt;password&gt;&lt;![CDATA[pass123]]&gt;&lt;/password&gt;                     &lt;dbname&gt;&lt;![CDATA[testdb]]&gt;&lt;/dbname&gt;                     &lt;initStatements&gt;&lt;![CDATA[SET NAMES utf8]]&gt;&lt;/initStatements&gt;                     &lt;model&gt;&lt;![CDATA[mysql4]]&gt;&lt;/model&gt;                     &lt;type&gt;&lt;![CDATA[pdo_mysql]]&gt;&lt;/type&gt;                     &lt;pdoType&gt;&lt;![CDATA[]]&gt;&lt;/pdoType&gt;                     &lt;active&gt;1&lt;/active&gt;                 &lt;/connection&gt;             &lt;/default_setup&gt;         &lt;/resources&gt;         &lt;session_save&gt;&lt;![CDATA[files]]&gt;&lt;/session_save&gt;     &lt;/global&gt;     &lt;admin&gt;         &lt;routers&gt;             &lt;adminhtml&gt;                 &lt;args&gt;                     &lt;frontName&gt;&lt;![CDATA[admin]]&gt;&lt;/frontName&gt;                 &lt;/args&gt;             &lt;/adminhtml&gt;         &lt;/routers&gt;     &lt;/admin&gt; &lt;/config&gt;   Also I want to assign that value to the variable for further use. Let me know your idea. What is the correct way to pluralize an initialism in which the final word is not pluralized by adding the letter "s"? VirtualBox 5.0.40 crashes the whole host since update to kernel 4.13.0-26-generic I received the updates through normal Software Updater, 10-Jan-2018. After this VirtualBox would not start any VM, complaining about dkms and asking to make modprobe vboxdrv. Following the advice I reinstalled virtualbox-dkms with:  sudo apt-get --reinstall install virtualbox-dkms   After this and a reboot I tried to start a VM which freezed the whole machine and a hard reboot was necessary.  Is there a way to make VirtualBox work with the latest kernels?  EDIT:  As suggested by N0rbert, the command:  apt-cache policy `dpkg -S VirtualBox | head -n1 | sed -e 's/://g' | awk '{print $1}'`  gives:   virtualbox-qt:   Installed: 5.0.40-dfsg-0ubuntu1.16.04.2   Candidate: 5.0.40-dfsg-0ubuntu1.16.04.2   Version table:  *** 5.0.40-dfsg-0ubuntu1.16.04.2 500         500 http://fr.archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 Packages         100 /var/lib/dpkg/status      5.0.18-dfsg-2build1 500         500 http://fr.archive.ubuntu.com/ubuntu xenial/multiverse amd64 Packages   EDIT (on 29-Mar-2018): Issue is resolved for me, with the Ubuntu Ubdate from today. I have seen that it had some virtualbox-updates, therefore I tried to boot with the most recent kernel again. Then I had to run  sudo apt-get --reinstall install virtualbox-dkms  And after this my virtual machines in VirtualBox started working without crashing the whole computer. Finally! In Gmail, what is the safest way to download, save & print all emails with a given label? Attempting to securely download all the emails with a given label in Gmail, save them to a single file, and print that file. More homework help.  Given the function $f:A \to B$.  Let $C$ be a subset of $A$ and let $D$ be a subset of $B$.  Prove that:  $C$ is a subset of $f^{-1}[f(C)]$  So I have to show that every element of $C$ is in the set $f^{-1}[f(C)]$  I know that $f(C)$ is the image of $C$ in $B$ and that $f^{-1}[f(C)]$ is the pre-image of $f(C)$ into $A$.  Where I'm stuck is how to use all of this information to show/prove that $C$ is indeed a subset.    Do I start with an arbitrary element (hey, let's call it $x$) of $C$? and then show that $f^{-1}[f(x)]$ is $x$?  I could use a little direction here...  Thanks. Why does the weighing balance restore when tilted and released How to preserve custom number formatting after closing a workbook? I have created a custom format ##,##0.0,,, CTRL+J %% in Excel 2010 to display  10000 as 0.1 100000 as 1.0 1000000 as 10.0 10000000 as 100.0 100000000 as 1,000.0 and so forth.  The problem I am facing is that once I apply this format, save and close the workbook, the next time I open it the format gets changed by multiplying by 10 (100000 is displayed as 10.0).  I don't understand how it is getting changed automatically the next time I open it. However, when I apply other formats they remain unchanged. Predefined Coordinate Systems missing in QGIS 2 in QGis 1.8 were lots of predefined coordinate systems (national projections). Where have they all gone in qgis 2.0? I specifically need the Gauß-Krüger-Projections Zone 1 to 5.  Is there any plugin to load those coordinate systems? Exporting 2D vector graphic from ArcScene to Illustrator How can I export 2d vector graphic from ArcScene so I can edit it with Adobe Illustrator? 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When I ssh into my  box, I get this message:  Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-32-generic x86_64)   * Documentation:  https://help.ubuntu.com/  New release '12.10' available. Run 'do-release-upgrade' to upgrade to it.  Last login: &lt;redacted&gt; $   But I don't intend to upgrade to 12.10, because Mythbuntu recommends using LTS releases only.  How do I suppress the "New release '12.10' available" message?  I don't want to be notified until the next LTS release is available.  I've already gone to Update Manager > Settings > Updates and selected "Notify me of a new Ubuntu version: For long-term support versions", but that didn't get rid of this message. Let L1 be the line passing through the point $P_1=(−11, 10, −1)$ with direction vector $\vec d_1=\begin{bmatrix}−2\\ 3\\ −1\end{bmatrix}t$, and let $L_2$ be the line passing through the point $P_2=(−8, 9, 10)$ with direction vector $\vec d_2=\begin{bmatrix}−1\\ 3\\1\end{bmatrix}t$. Find the shortest distance, $d$, between these two lines, and find a point $Q_1$ on $L_1$ and a point $Q_2$ on $L_2$ so that $d(Q_1,Q_2) = d$.   I dont really understand how to properly approach this question, how do i start?