Why is our new clan member ineligible for war?
Requirements for a clan war?
Interfaces with static fields in java for sharing 'constants' I'm looking at some open source Java projects to get into Java and notice a lot of them have some sort of 'constants' interface.  For instance,  has an interface called , and most other core classes implement this interface. The interface is riddled with static members. Is there a reason for this approach, or is this considered bad practice? Why not use enums where it makes sense, or a static class?  I find it strange to use an interface to allow for some sort of pseudo 'global variables'.  public interface PConstants {    // LOTS OF static fields...    static public final int SHINE = 31;    // emissive (by default kept black)   static public final int ER = 32;   static public final int EG = 33;   static public final int EB = 34;    // has this vertex been lit yet   static public final int BEEN_LIT = 35;    static public final int VERTEX_FIELD_COUNT = 36;     // renderers known to processing.core    static final String P2D    = "processing.core.PGraphics2D";   static final String P3D    = "processing.core.PGraphics3D";   static final String JAVA2D = "processing.core.PGraphicsJava2D";   static final String OPENGL = "processing.opengl.PGraphicsOpenGL";   static final String PDF    = "processing.pdf.PGraphicsPDF";   static final String DXF    = "processing.dxf.RawDXF";     // platform IDs for PApplet.platform    static final int OTHER   = 0;   static final int WINDOWS = 1;   static final int MACOSX  = 2;   static final int LINUX   = 3;    static final String[] platformNames = {     "other", "windows", "macosx", "linux"   };    // and on and on  } Determine which app is drawing on top of other apps? Is there a way to determine which application is drawing on top of other applications?  For example, Facebook Messenger app can draw the chat bubbles on top of everything, but how do I know which app is doing this?  My problem:  I have an app which is drawing ads on top of everything and I wanna know which app is doing this. Not just to uninstall it, but to warn everyone that uses this app. (I didn't install any application recently and I already verified the recent updates.)  I tried to use the Dump View Hierarchy for UI Automator from the Android Studio, but it seems that the applications that draw on top can't be selected this way.  (Click image to enlarge) Exposing database IDs - security risk? I've heard that exposing database IDs (in URLs, for example) is a security risk, but I'm having trouble understanding why.  Any opinions or links on why it's a risk, or why it isn't?  EDIT: of course the access is scoped, e.g. if you can't see resource foo?id=123 you'll get an error page. Otherwise the URL itself should be secret.  EDIT: if the URL is secret, it will probably contain a generated token that has a limited lifetime, e.g. valid for 1 hour and can only be used once.  EDIT (months later): my current preferred practice for this is to use UUIDS for IDs and expose them. If I'm using sequential numbers (usually for performance on some DBs) as IDs I like generating a UUID token for each entry as an alternate key, and expose that. Does existence of $\gcd$ implies PID? How many String objects will be created when using a plus sign? Underscores in words (text) How can I produce the text Word_one_two in LaTeX?  I tried:  Samp\_Dist\_Corr   But, it doesn't quite look right. Also, I want it in the typewriter font, so actually, I'm doing:  \texttt{Samp\_Dist\_Corr}   I find it looks a bit like the underscore is merging in to the bottom of the "D", but maybe it's just because of the typewriter D? Left ideals of $M_n(K)$ Can you explain Parzen window (kernel) density estimation in layman's terms? A Polygon is inscribed in a circle $\Gamma$ A regular polygon P is inscribed in a circle $\Gamma$. Let A, B, and C, be three consecutive vertices on the polygon P, and let M be a point on the arc AC of $\Gamma$ that does not contain B. Prove that  $MA\cdot MC=MB^2-AB^2$  I inscribed the polygon P in the unit circle and let B=1. Past this, I'm not really sure how to proceed. It might be helpful to have M at 1 as well but given that the polygon would have the n-th roots of unity in it B seemed like a good choice. What would be a good way to proceed from here? I need to know the ip address of another machine in a lan network.  What is the Windows command for getting ip address from machine name and vice versa? Number of ring homomorphisms from $\mathbb Z_{12}$ to $\mathbb Z_{28}$. Question:      Find the number of non trivial ring homomorphisms from $\mathbb Z_{12}$ to $\mathbb Z_{28}$. ($f$ is not necessarily unitary, i.e., $f(1)$ need not be $1$.)    Suppose $f$ is a ring homomorphism from $\mathbb Z_{12}$ to $\mathbb Z_{28}$.  Consider $f$ as a additive group homomorphism.  Let $k= |\ker f|$ and  $ t = |\operatorname{im}(f)|$. Then $k\mid 12$ and $t\mid 24$ and $kt=12$, by first isomorphism  theorem of groups.  There are two possibilities $k=3$, $t=4$   and $k=6$, $t=2$.  For the first case $f$ should map $1$ to an element of the subgroup generated by $7$ as there is a unique subgroup of $\mathbb Z_{28}$ of order $4$ generated by $7$. For the second case $1$ has to map to $14$, for the same reasoning.  So there are at most two ring homomorphisms from $\mathbb Z_{12}$ to $\mathbb Z_{28}$. Question is how to check the possible maps which are ring homomorphisms.  Thanks. /ɪ/ sound when not stressed I've seen that some words in English are pronounced with the /ɪ/ sound when the vowel is not stressed.  Some examples include: pocket /ˈpɒkɪt/, comet /ˈkɒmɪt/. But hundred /ˈhʌndrəd/.  Is there any pronunciation rule here when the words end in /t/? Continuous function on R which tends to infinity on open interval must have a minimum Suppose we have $f : \mathbb{R} \to \mathbb{R}$ continuous and $$\lim\limits_{x \to \pm \infty} f(x) = \infty.$$  Then must $f$ have a minimum on $\mathbb{R}$?  Intuitively it seems so, and it's easy to prove for some arbitrary closed interval in $\mathbb{R}$ with the Extreme Value Theorem, but how can we apply that to an open interval like $(-\infty, \infty)$? Android Phone SD Card Problem My Samsung Galaxy Admire phone is saying that an SD card isn't found when the SD card is inside the phone: it shows "Please insert SD Card".  What could be wrong? Assessing approximate distribution of data based on a histogram Cannot detect wireless driver intel ac wireless 9560 [logs included] Currently using Ubuntu 18.04, and my wireless driver is not being detected.  I've included a .  $ dmesg | grep iwl [    6.212724] Loading modules backported from iwlwifi [    6.212724] iwlwifi-stack-public:master:6988:0d8892f2 [    6.224583] iwlwifi 0000:00:14.3: enabling device (0000 -&gt; 0002) [    6.229811] iwlwifi 0000:00:14.3: Direct firmware load for iwl-dbg-cfg.ini failed with error -2 [    6.230540] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-39.ucode failed with error -2 [    6.230547] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-38.ucode failed with error -2 [    6.230552] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-37.ucode failed with error -2 [    6.230557] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-36.ucode failed with error -2 [    6.230562] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-35.ucode failed with error -2 [    6.236670] iwlwifi 0000:00:14.3: loaded firmware version 34.0.0 op_mode iwlmvm [    6.248314] iwlwifi 0000:00:14.3: Detected Intel(R) Dual Band Wireless AC 9560, REV=0x318 [    7.264081] iwlwifi 0000:00:14.3: SecBoot CPU1 Status: 0x3, CPU2 Status: 0x2477 [    7.264084] iwlwifi 0000:00:14.3: Failed to start INIT ucode: -110 [    7.276165] iwlwifi 0000:00:14.3: Failed to run INIT ucode: -110   sudo modprobe iwlwifi returns no output. Why is it that logistic regression becomes unstable when classes are well-separated? What does well-separated classes mean? I would really appreciate if someone can explain with an example. Is there a printable version of a reference manual for all TeX primitives? I need to do an  request in JavaScript. What's the best way to do that?  I need to do this in a Mac OS X dashcode widget. I read in several places, including Wikipedia, that a tessellation of the plane by a single, convex, $n-$sided polygon is not possible for $n\geq7$. I was not able to locate a proof, or a paper that discusses this. Maybe it is too trivial, but I am not able to figure it out myself.   So I would like to ask you for help. Where can I find a proof for this?  Also, I am interested in the mathematical background behind plane tiling (especially periodic), If you can suggest papers on the topic it would really help.