I am not exactly sure why the hashCode() method is returning the same value. Can someone provide more detailed explanation of this?  Source code (Java):  public class Equality {  public static void main(String [] args) {     String str = "String";     String strOne = new String("String");        System.out.println(str == strOne);     System.out.println(str.equals(strOne));      System.out.println(str.hashCode());     System.out.println(strOne.hashCode());  }   }
What issues / pitfalls must be considered when overriding equals and hashCode?
For which $n$ is the sum: $$\sum_{k=0}^{n}10^k$$ a prime number? Are they finite? Why are second order linear PDEs classified as either elliptic, hyperbolic or parabolic? Is there a geometric interpretation of second order linear partial differential equations which explains why they are classified as either elliptic, hyperbolic or parabolic, or is this just a naming convention? That is, do they have any relation with actual ellipses, hyperbolas and parabolas? Using bools in calculations to avoid branches Use Stack Exchange icon for Stack Exchange blog posts in the Community Bulletin is used to host global Stack Exchange blog posts and is using favicon of Stack Exchange itself. All good. However, when published in the bulletin, the Meta Stack Exchange icon is used for some reason:    Can it be changed please to using the &quot;full&quot; icon? How do "pet" Walkers help ward off other Walkers? In both the comics and the show, Michonne first appears with two walkers that she essentially keeps as pets.    The comics sort of half-explain this - as per :     She notices walkers don't attack one another and hacks off the arms and lower jaws of Mike and Terry. She chains them up by their necks to use them as escorts for an escape that was successful.   In , we see that even if they still sort of smell like Walkers, the Walkers can smell/detect the living and will attack.  In ,      We see Andrea effectively making a new "pet" so that she can use to deter the Walkers that she comes across on her trip to the prison. Along the trip, she is shown to come within close range of Walkers, but they give her space when she points the "pets" in the right direction.   Why would the Walkers not just attempt to go around the "pets"? What about them creates an effective protective barrier? Do Mandalorians truly never remove their helmets? In episode 3 of The Mandalorian, it is said that Mandalorians never remove their helmets for any reason. Really? Not even to sleep or bathe? Is there any canonical source for this idea? I’m going to assume that the “never” implies “Never removes their helmets in public…” right?  But in flashback scenes to the Mandalorian’s childhood, nobody is really pictured wearing Mandalorian armor let alone helmets. They simply seemed like basic humans who might just be unified by wearing maroon wardrobes all the time.  So what is the deal with this claim? What is the canonical context of the claim?      Looking for in-universe, canonical explanations; not armchair speculation and theories. If none (currently) exist, legends explanation would suffice. Regardless, please provide references and context. How to replace subscript symbols SEO regarding using separate  tags for the logo and website name Is is true &lt;h1&gt; tag should not have more than 1 on every page for SEO?   Every pages on the header, it includes and &lt;h1&gt; tag. Website Name which show an image from logo class, like this:  &lt;div id="header"&gt;   &lt;h1 class="logo"&gt;      &lt;a href="#"&gt;Website Name&lt;/a&gt;   &lt;/h1&gt; &lt;/div&gt;   and I also include &lt;h1&gt; on the contact page, help, etc and article page for example:  &lt;h1&gt;Contact Us&lt;/h1&gt; &lt;h1&gt;Name of the Article Title here&lt;/h1&gt;   On the homepage, it just has one &lt;h1&gt; for the logo Site Name... other pages have 2 &lt;h1&gt; tags Capturing Blue Screen of Death (BSOD) screen Possible Duplicate:          Sometimes I get a BSOD screen for a split second and I have no chance to see the cause of it. It also happens when I am not at the computer. The event log doesn't have enough information. Is there a way or tool that captures the screen when it happens so I can look at the cause later.  I already did a memory diagnostics test so that's not the problem. Given  $$ y_n=\left(1+\frac{1}{n}\right)^{n+1}\hspace{-6mm},\qquad n \in \mathbb{N}, \quad n \geq 1. $$ Show that $\lbrace y_n \rbrace$ is a decreasing sequence. Anyone can help ?  I consider the ratio $\frac{y_{n+1}}{y_n}$ but I got stuck. How to run a LaunchAgent that runs a script which causes failures because of System Integrity Protection After upgrading to Mojave, my rsync based backup script run via a launch agent in ~/Library/LaunchAgents, could no longer read some directories in ~/Library. Test for convergence of the series $\sum_{n=2}^\infty\frac{1}{(\ln n)^{\ln n}}$ I am not sure what caused this error, but here is what the whole error says, and also this is sitting as a notification, and preventing me from updating any software using Update Manager - Please provide some assistance or tell me how to figure out what to do to fix it.  Could not calculate the upgrade  An unresolvable problem occurred while calculating the upgrade.  Please report this bug against the 'update-manager' package and include the following error message: 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.' How to customize the Ubuntu Live CD? I would like to customize Ubuntu live CD by installing some additional packages. I have followed   but it doesn't seems to work. Can anyone provide clear instructions?   Note: I do not prefer Remastersys, manual way will be appreciated.  Customization  Packages that I want to install:   Thunderbird    Samba    SSH       Changes that I need:   Remove Games menu from the Application menu Firefox shortcut on Desktop Radiance as the default Theme Different default Ubuntu Wallpaper   Configuration file changes   I want the panel to be placed at the bottom I want to paste my Samba configuration file instead of default Samba configuration I have few Firefox shortcuts and folders I would like to show that in Desktop Also it will be nice if you say me how to change the icon sets   Recent Updates   I have customized Ubuntu 10.10 with Firefox shortcuts and few folders on desktops. Everything went smooth. But the installer gets crashes after choosing the timezone. How do i fix this issue? Also setting wallpaper affects the login screen. The wallpaper which i set is displayed on the login screen also. I just want the default one for the login screen. Prove $\gcd(a+b, a-b) = 1$ or $2\,$ if $\,\gcd(a,b) = 1$ I want to show that for $\gcd(a,b) = 1$ $a,b \in Z$   $\gcd(a+b, a-b) = 1$ or $\gcd(a+b, a-b) = 2$ holds.      I think the first step should look something like this:      $d = \gcd(a+b, a-b) = \gcd(2a, a-b)$   From here I tried to proceed with two cases. 1: $a-b$ is even, which leads to $\gcd(a+b, a-b) = 2$ 2: $a-b$ is odd, which leads to $\gcd(a+b, a-b) = 1$  My main problem I think is, that I do not know how I should include $\gcd(a,b) = 1$ in the proof.  Any help is appreciated. Thx in advance. Cherio Woltan Prevent direct access to a php include file I have a php file which I will be using as exclusively as an include. Therefore I would like to throw an error instead of executing it when it's accessed directly by typing in the URL instead of being included.  Basically I need to do a check as follows in the php file:  if ( $REQUEST_URL == $URL_OF_CURRENT_PAGE ) die ("Direct access not premitted");   Is there an easy way to do this? Add custom command in the open with dialog? In earlier versions of Ubuntu (10.10-) there was an option in the "open with" tab in the properties window, to add a custom command to open a file. However, this is no longer the case in Ubuntu 11.10. Is there any way that I can add these file type associations with a command of my choice rather than the applications detected by the system. Finding the Transform matrix from 4 projected points (with Javascript) What computer components are currently vulnerable to magnets? When I first started using computers, law of the land in computer class was never bring magnets near anything computer related, lest you lose all your data or screw up your monitor.  Now I am pretty sure magnets will still royally mess up a standard hard drive, and I know for a fact they screw up a CRT monitor.  Though I am also pretty sure they do not screw up a LCD monitor?  Now I have my phone which uses magnets to determine if it's docked, and it made me wonder.  Is it the power of the magnet preventing data loss or the sheer fact that whatever memory type in the phone is immune to it?  What about ear buds, as I know those have tiny magnets in them. Are those capable of damaging any electronic device currently in use?  I'm wondering if I'm being paranoid, but I really am not sure what magnets will damage and what they won't!  Is there a list, or rule of thumb for determining what will be hurt by magnets and what won't be? I don't really get why these hyperbolic functions are named after trig functions. Can someone enlighten me?