mFusedLocationProviderClient = null
What is a NullPointerException, and how do I fix it?
How does the bounty system work? It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center Let $f$ be a complex function with the property that $f^{(n)} = 0$.  Does this imply that $f$ is a polynomial?  If so, why?  Upon thinking about this problem myself, I can easily observe that every $n$ degree polynomial satisfies $f^{(n+1)} = 0$.  Still, this doesn't show that some non-polynomial function couldn't also have this property. Hamiltonian Monte Carlo for dummies Could you provide a step-by-step for dummies explanation of how Hamiltonian Monte Carlo work?  PS: I've already read the answers here, , and here, , and here,  and they do not address it in a step-by-step way. Show $\sum\limits_{n=0}^{\infty}{2n \choose n}x^n=(1-4x)^{-1/2}$ How do you prove that $\sum\limits_{n=0}^{\infty}{2n \choose n}x^n=(1-4x)^{-1/2}$? I tried to identify the sum as a binomial series, but the $4$ and the $-1/2$ puzzle me. (This series arises in studying the first passage time of a simple random walk.) Fix Accessibility of the sites on the leagues (and other pull downs that share the same code path) please The  site picker seems to be ordered on-site statistics instead of alphabetically:  This makes it very hard to find Photography, Physics, and Philosophy (for example) since they are nowhere near each other in the list. I’m open to a better solution, but as it stands, this feels a little too user-hostile to assume everyone is only interested in the first 3 to 5 top visible hits in the ordered list.  Scanning pages of unorganized contents is not optimal Keyboard input should filter and not just jump around  It also breaks accessibility when someone wishes to access the list from a keyboard (or a slower input control) as opposed to a mouse and visually. Convert Month Number to Month Name Function in SQL I have months stored in SQL Server as 1,2,3,4,...12. I would like to display them as January,February etc. Is there a function in SQL Server like MonthName(1) = January? I am trying to avoid a CASE statement, if possible. Replace non-numeric with empty string Is static HTML the fastest? I would really like to see all of my questions and answers on the profile page, even if some of them were deleted, and I don't have enough rep to see them on the site. (Note that some questions are  after 30 days or 1 year, and the author might be oblivious about what happened.)   , the &quot;deleted recent [questions/answers]&quot; links in one's own user profile now list all respective posts that were deleted in the past 60 days, rather than just those that were originally posted in the last 60 days. , users with the &quot;access to moderator tools&quot; privilege (10k+ on designed sites, 2k+ on beta and non-designed sites) can use the search operator deleted:1 to see all their own deleted posts. , deleted questions and answers that were posted in the past 60 days, can be seen using the &quot;deleted recent questions&quot; and &quot;deleted recent answers&quot; links on the questions and answers tabs (at the bottom of the tab) in your user profile. For older posts: as of 2013-04-23 you can  if you already have a link to them, but they still aren't linked from the user profiles (not even just for you). Nor do you see inbox notifications for comments on them if you come back a few hours later. You have to have thought to bookmark your question, or you have to go digging for it in your browser history. Determining application path in a Python EXE generated by pyInstaller How can one show that for triangles of sides $a,b,c$ that   $$\frac{a}{b+c}+\frac{b}{c+a}+\frac{c}{a+b} &lt; 2$$  My proof is long winded, which is why I am posting the problem here.   Step 1: let $a=x+y$, $b=y+z$, $c=x+z$, and let $x+y+z=1$ to get   $\frac{1-x}{1+x}+\frac{1-y}{1+y}+\frac{1-z}{1+z}&lt;2$  Step 2: consider the function $f(x)=\frac{1-x}{1+x}$, and note that it is convex on the interval (0,1), so the minimum of   $\frac{1-x}{1+x}+\frac{1-y}{1+y}+\frac{1-z}{1+z}$  is reached when the function takes the extreme points. i.e. $x=y=0, z=1$.    But going back to the fact that this is a triangle, we note that $x=y=0 \implies a=0$ which is not possible, so the inequality is strict. Using "on" vs. "in"? Consider the following sentence:     I am developing an application to be installed on Android.   And this:     This has been a major flaw in Android...   To be clear I am unsure of the usage of "in" vs. "on". When should I use "in" and when to use "on"? Proving the snake lemma without a diagram chase Why aren't people voting for questions? If every ideal is principal show the same is true for the image of a homomorphism. Windows 10 sees much more monitors than I have A teacher wants to randomly form two teams of 5 students from a group of 5 girls and 5 boys for a sports activity. A teacher wants to randomly form two teams of 5 students from a group   of 5 girls and 5 boys for a sports activity. Two of the girls, Ann and   Alice, are selected as team leaders. Find the probability that one   team has exactly 3 girls.   If i do this way $$\dfrac{{3 \choose 2}{5\choose 2}{1\choose 1}{3\choose 3} \times 2!}{{8 \choose 4}{4 \choose 4}} = \dfrac{6}{7}$$  Which turns out to tally with the answer. But i got one big question, is my way correct. Do i really need to times $2$ here? Please see my link below to my previous question cause the previous question make me doubt if i should times $2$. Why do you need to know who I know on Google? I just created a SE account using my Google account. It said that it needs to "Know who you are on Google" (I guess my connections). As far as I know, SE is not a social network. I can't even follow other people (seeing when they post questions and answers).  What is the reason you need to know my Google connections?  This was on code review. Actually I have an account there, but for some reason it asked me to reconnect. This is the same on MSO; one sees this explained as "This app is requesting permission to associate you with your public Google profile": Does 'rm .*' ever delete the parent directory? The expression .* is expanded by bash to include the current and parent directories:  $ ls -la total 2600 drwxrwxrwx   2 terdon terdon 2162688 Sep 10 16:22 . drwxr-xr-x 142 terdon terdon  491520 Sep 10 15:34 .. -rw-r--r--   1 terdon terdon       0 Sep 10 16:22 foo $ echo .* . ..   If I run rm -rf .* on my Debian using GNU bash, version 4.2.36(1)-release and rm from rm (GNU coreutils) 8.13, I get this message:  $ rm -rf .* rm: cannot remove directory: `.' rm: cannot remove directory: `..'   Is this a GNU thing or is it POSIX? Are there any *nix systems where the command above will silently delete . and ..?  Also, is this a safety feature of the shell or of the rm command itself? What exactly is heat? Is it energy?  Is it energy per unit volume?  Is it energy per unit time i.e power?  What is it?