Using Objects#hash(Object...) for hashCode method?
Use Objects.hash() or own hashCode() implementation?
Powerset of set with empty sets I am working on a problem with the following set:  $$S =  \{\varnothing,\{\varnothing\}\}$$  My solution was: $P(S) = \{\varnothing, \{\varnothing\},\{ \varnothing , \{ \varnothing \}\}\}$, but the solution on the textbook shows: $P(S) = \{ \varnothing , \{ \varnothing \}, \{\{\varnothing\}\}, \{ \varnothing , \{ \varnothing \}\}$  Where does the $\{\{\varnothing\}\}$ come from?  Thanks What is the "wheel" user in OS X? Blogs link from the not existing community page refers to 404 The “blogs” link from the , e.g:        refers to another not existing page:        Looks like blogs link should refer to the same page as for “blog” link in the footer: How do I drag and drop files into an application? I've seen this done in Borland's  environment, but I'm not sure how to go about it for a C# application I'm working on. Are there best practices or gotchas to look out for? My objective here is really simple -- I'm trying to set an NSString to some test data, then return the class, which should be NSString. Here's my code:  NSString* stringer = [NSString stringWithFormat: @"Test"]; NSLog(@"%@", [stringer class]);   The log says that the class is NSCFString, not NSString. What's going on here? Box around single element in list Is there any way in latex to create a simple box around one item in a list?  I tried both \framebox, and \fbox, none of them worked  \begin{enumerate}[label=\Alph*),ref=\Alph*] {\color{red}\item null.}  \item lik vektdifferansen $GT - GK$. \item lik vektsummen $GT + GK$. \item lik vekten av $K$. \end{enumerate}   Works, but   \begin{enumerate}[label=\Alph*),ref=\Alph*]  {\color{red}  \fbox{ \item null.} }   \item lik vektdifferansen $GT - GK$. \item lik vektsummen $GT + GK$. \item lik vekten av $K$. \end{enumerate}   Does not. So yeah, any way to box a single entry in a list? Broken screen while debug mode was disabled. How can I re-enable adb? The screen of my phone is physically broken, so it doesn't display anything, but the touch aspect does seem to be working, as I can unlock my phone, and get haptic feedback.  Before I go to get it replaced, I'd like to back up some personal data from the built-in memory to the SD card. I'm fairly certain that if I can get adb to recognize the device, then I can use  to see where I am touching the screen and do what I need to do. Problem is, when I plug it in, it's not recognized, while my emulator is.  I suspect that I might not have USB debugging enabled, which I think is necessary for adb to work. If this is the case, can someone give me screenshots of their Droid X (running 2.3.X) going from the home screen, through all the menus, to activating debug mode? Hopefully I can do it by dead reckoning and adb from there.  Edit: I haven't changed anything about the ROM or launcher; it's all stock. What is the difference between    a parameter passed by reference a parameter passed by value?   Could you give me some examples, please? Drush hangs when trying to bootstrap Drupal I was compiling a tool called Rejoystick so I installed a few packages and dependencies. But now I don't need it any more so I removed those packages. Running apt-get shows that I have some packages that are automatically installed and are no longer needed.   But I have a bad experience with apt-get autoremove. It broke my desktop environment when I uninstalled wine some time ago. Luckily, I had a clonezilla partition backup then, but this time, I don't have a backup. So I'm cautious. Running apt-get shows these packages are orphaned     gir1.2-gtk-2.0 libasound2-dev libavahi-client-dev libavahi-common-dev   libcaca-dev libcairo-script-interpreter2 libdbus-1-dev libdrm-dev   libexpat1-dev libfontconfig1-dev libfreetype6-dev libgl1-mesa-dev   libglu1-mesa-dev libharfbuzz-dev libharfbuzz-gobject0 libice-dev   libpcre3-dev libpcrecpp0 libpixman-1-dev libpng12-dev libpthread-stubs0-dev   libslang2-dev libsm-dev libx11-dev libx11-doc libx11-xcb-dev libxau-dev   libxcb-dri2-0-dev libxcb-dri3-dev libxcb-glx0-dev libxcb-present-dev   libxcb-randr0-dev libxcb-render0-dev libxcb-shape0-dev libxcb-shm0-dev   libxcb-sync-dev libxcb-xfixes0-dev libxcb1-dev libxcomposite-dev   libxcursor-dev libxdamage-dev libxdmcp-dev libxext-dev libxfixes-dev   libxft-dev libxi-dev libxinerama-dev libxrandr-dev libxrender-dev   libxshmfence-dev libxxf86vm-dev mesa-common-dev x11proto-composite-dev   x11proto-core-dev x11proto-damage-dev x11proto-dri2-dev x11proto-fixes-dev   x11proto-gl-dev x11proto-input-dev x11proto-kb-dev x11proto-randr-dev   x11proto-record-dev x11proto-render-dev x11proto-xext-dev   x11proto-xf86vidmode-dev x11proto-xinerama-dev xorg-sgml-doctools xtrans-dev   zlib1g-dev   I'm not sure if I should run apt-get autoremove. I was searching details related to each of these packages so that I can understand which ones are needed but they all seem important e.g.     gir1.2-gtk-2.0    I have Cinnamon, GNOME and Unity installed, I think apt-get autoremove will break something. Any help will be appreciated.   Thanks for reading. If I create just a basic hello.tex file an compile it using   pdflatex hello.tex   The pdflatex program is creating a plethora of file which is a little annoying. Currently it writes all those files about which I really don't care:  hello.aux, hello.log, hello.nav, hello.out, hello.snm, hello.toc   Is there a way to tell pdflatex to only write hello.pdf if the build is successful ? If not, can I specify the output directory of those files ? Maybe I could just write them in /tmp. What would be an English equivalent for the Mexican Spanish word tocayo? How do I log into my Linux laptop if I have forgotten both the username and password? Which of the following sentences is/are incorrect? ("Permit" vs. "allow" vs. "let") Which of the following sentences is/are incorrect? Why?   The visa permits you to study for two months. My father would never allow me to study English Let me to go. You're hurting me.   This is question from an English learning book. All the sentences seem right to me. Do you know which one is incorrect and why? So I have an SQL dump file that needs to be loaded using mysql_query(). Unfortunately, it's not possible to execute multiple queries with it.  -> It cannot be assumed that the mysql command-line client (mysql --help) is installed -- for loading the SQL file directly  -> It cannot be assumed that the mysqli extension is installed  /* contents of dump.sql, including comments */ DELETE FROM t3 WHERE body = 'some text; with semicolons; scattered; throughout'; DELETE FROM t2 WHERE name = 'hello'; DELETE FROM t1 WHERE id = 1;   The explode() below won't work because some of the dump content's values contain semicolons.  $sql = explode(';', file_get_contents('dump.sql')); foreach ($sql as $key =&gt; $val) {     mysql_query($val); }   What's the best way to load the SQL without modifying the dump file? I have multiple characters linked to a blender file, but i moved the original character files and now blender is sating they're missing.  Is it possible to get blender to find the missing blender files like it finds missing image files so that i can preserve the previously made animation?  On a side note is there a way to also view a list of all the missing files? I was doing a duplicate content search on the web for our site content and found that someone has downloaded/mirrored our entire website and is hosting it on a subdomain of their own main domain. When I check the WHOIS database, no details of the user are available.  Why do people do this when it is clearly a copyright infringement - is it an SEO thing?  What is the best way of dealing with these individuals? redirecting output of running background job in bash in bash I have some jobs running, in background. They are always producing random irrelevant error messages that pollute the terminal. I am not always so prompt to start them with the 2&gt;&amp;1 &gt; /dev/null redirect. How can I redirect the output when they are already running? POSTFIX main.cf permission denied I am trying to set up a postfix server for smtp relay. Centos 5.5  I have followed  but am getting a FAILED error when trying to restart or reload postfix.  When I do:  cat maillog   I get:  fatal: open /etc/postfix/main.cf: Permission denied   Here is what I have tried:  chown postfix /etc/postfix/main.cf chmod u+rwx /etc/postfix/main.cf   After that, I do:  ls -l /etc/postfix/main.cf   Which gives me:  -rwx------. 1 postfix anotheruser 27531 Apf 29 12:19 /etc/postfix/main.cf   No dice. Same error. I even tried temporarily doing chmod 777 but got same error.  Any ideas on the permissions problem? I am assuming it is running the service as the postfix user.  Thanks Levels or First Differences, VECM or VAR for Ultimate Impulse Response Functions?