In Selenium 2 - Java, what's the difference between  ChromeDriver driver = new ChromeDriver();  and  WebDriver driver = new ChromeDriver();  ? I've seen both of these used in various tutorials, examples, etc and am not sure about the difference between utilizing the ChromeDriver vs WebDriver objects.
I have seen this mentioned a few times and I am not clear on what it means. When and why would you do this?   I know what interfaces do, but the fact I am not clear on this makes me think I am missing out on using them correctly.   Is it just so if you were to do:  IInterface classRef = new ObjectWhatever()   You could use any class that implements IInterface? When would you need to do that? The only thing I can think of is if you have a method and you are unsure of what object will be passed except for it implementing IInterface. I cannot think how often you would need to do that.   Also, how could you write a method that takes in an object that implements an interface? Is that possible?
I am curious how people picture geometrically how the covariant derivative acts with regards to vector fields. I understand that it is merely an object which has been defined for some use and obeys certain conditions but how would you picture such a thing geometrically? In other words, when someone asks you what the covariant derivative is, how do you explain it in absence of a formal definition? Possible Duplicate:     Which one of these is correct?  It is I who am at fault. It is me who is at fault.  The word &quot;is&quot; is a conjugation of &quot;be&quot; which is a linking verb. I also want to know the same for 2nd person.  It is you who are at fault. It is you who is at fault. Prove that for every positive integer $n$, $1/1^2+1/2^2+1/3^2+\cdots+1/n^2\le2-1/n$ Problem from iOS 10.1.1 to 10.2.1.  I have no photos at all on my iPhone yet in settings it says my photo library is taking up ~200MB of space. The number of space being taken up keeps changing constantly(in the settings app on my phone). In iTunes, the storage bar at the bottom does(when in the sync menu) not show photos.           What is taking up this storage, and how can I reduce it?  Troubleshooting:   I disabled iCloud photo library and iCloud photo stream, still showing the same thing. Tried doing what @User9125 said, didn't work. I had set the date all the way back when I first got my phone, nothing showed up. Rebooting I had hundreds of photos in Whatsapp, I deleted them but I didn't get the storage back. It didn't even make a dent in the amount of storage being used by Photos so I don't think a third-party app could be taking up this storage. I don't think a system app is taking this space either, because I cleared the pictures in mail and messages. I tried using (through sideloading) in Secure Mode and Fast Mode, but it did not clear up the photos. Is there a way to refresh Notepad? Say, for example, that there's one process that's writing to a file. While the process is running, I opened the file in notepad. The process keeps  writing to the file.   Other than closing and reopening the file, is there any way for me to "refresh" the data that notepad is showing? How to interpret regression coefficients when response was transformed by the 4th root? I'm using fourth root (1/4) power transformation on my response variable, as a result of heteroscedasticity. But now I'm not sure how to interpret my regression coefficients.   I assume that I would need to take the coefficients to the fourth power when I back-transform (see below regression output). All of the variables are in units of dollar in millions, but I would like to know the change in dollar in billions.    While holding the other independent variable constant, a billion dollar change in fees, on average, leads to a change of 32 (or 32,000 dollars) in collections. I take 0.000075223 * 1000 (to get to billions) ^ 4 = 0.000032. Now do I multiply this number by 1 million or 1 billion (the original unit of the dependent variable is in millions)?  lm(formula = (Collections^(1/4)) ~ Fees + DIR)                   Estimate      Std. Error  t value            Pr(&gt;|t|) (Intercept)   2.094573355     0.112292375   18.653  0.0000000000000151 Fees        **0.000075223   **0.000008411    8.943  0.0000000131878713 DIR           0.000022279     0.000004107    5.425  0.0000221138881913 Can we actually discourage downvotes? Before you disagree with me with a downvote, or just want to be funny, please hear me out. From the :  The upvote privilege comes first because that's what you should focus on: pushing great content to the top. Downvoting should be reserved for extreme cases. It's not meant as a substitute for communication and editing.  I have honestly never seen a downvote reserved for an extreme case. The process is usually 1) downvote post if it's bad and don't comment. (Not much of a process, is it?) As you stay on the site longer and longer, you develop a carelessness towards downvotes (as I have), but for new users, it's really discouraging.  question inspired me to [ask balpha to] make , which is a list of users with 1 rep who have the  badge. That's the closest I could get to new users who deleted their own posts after downvotes came in. Don't get me wrong, I know the argument about being nice to new users very well, but I still believe it to be an issue. And since , users are much more inclined to go the lazy route and downvote bad questions. No alternative measures (see below) are taken, for the most part. Personally, I leave a comment and don't downvote until the asker shows no interest in fixing their post. The only other measure taken to discourage downvotes (on answers) is the -1 rep punishment to the downvoter, which is absolutely meaningless and inconsequential anyways. How are we supposed to educate new users when we don't teach them what to do, don't direct them to the FAQ, and discourage them with downvotes right off the bat?  Instead of voting down: If the post is spammy or offensive — flag it. If the question is duplicate or off-topic — flag it for moderator attention. If something is wrong, please leave a comment or edit the post to correct it.  We claim to discourage downvoting, yet I see answers like  that encourage us to downvote first and ask questions later when a question is simply unclear or effortless. It's just an awful chain reaction. A new user comes to the site asking a question, but that doesn't work out too well, so they get downvotes, delete the question in shame, and don't get the help they deserve as a fellow writer of code and programmer. Strip away the quality of the site for a moment: the core functionality of this site, and the only reason I and a lot of other users are (still) on it, is to receive and give help to/from others. I enjoy making sure fellow programmers get the answer they need, because this site has helped me get mine when I needed them. Quality can still be maintained if content is fixed rather than downvoted more often. So can we stop discouraging new users from continuing to use this site and actually start to discourage downvoting? I think we need to encourage effort towards teaching and helping new users understand the system and why their post is bad rather than slapping them in the face with downvotes that they don't know how to interpret anyways. I'm leaving ways we can do this up to others. My first thought was to increase the punishment for downvoting answers and to no longer make question downvotes free, but those wouldn't be well-received, judging by the history of similar suggestions. . Preventing LibreOffice from using smart quotes (“ ”) instead of (dumb) straight quotes? I use LibreOffice Calc to make lists of programs with different parameters to run on an hpc cluster. For each batch of commands I must do a find and replace on the smart quotes, as they cause errors in command line arguments. It would be nice to cut this step out of my work flow. Does anyone know how I might change the default punctuation used?  Edit: Apparently the title font transforms dumb quotes into smart quotes.  Smart quotes have a different symbol depending on if they are at the start or end (“ ”)  Dumb quotes use the same symbol for the start and the stop ( " ) How many different permutations are there of the sequence of letters in "MISSISSIPPI"? Is there any explanation for why the other 2 schools in the TriWizard tournament are both single-gender, unlike Hogwarts?  Was single-gender education normal in wizarding world with Hogwarts being the exception?  Was this some special intentional literary trick on Rowling's part or on movie creators'?    Here's the evidence from the movies:  Durmstrang Institute is boys-only:    Beauxbatons Academy of Magic seems to be an all-girl school: I have two atoms, both of which are either bosons or fermions, with four allowed energy states: $E_1 = 0$, $E_2 = E$, $E_3 = 2E$, with degeneracies 1, 1, 2 respectively.  What's the difference between the partition functions of a pair of two bosons and that of a pair of two fermions? Why use sucrose rather than glucose in an injectable vaccine? These are the ingredients of :  Medicinal:  mRNA  Non-medicinal:  ALC-0315 = ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate) ALC-0159 = 2-[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide 1,2-Distearoyl-sn-glycero-3-phosphocholine cholesterol dibasic sodium phosphate dihydrate monobasic potassium phosphate potassium chloride sodium chloride sucrose water for injection   Sucrose is broken up into glucose and fructose by digestion, and so it normally never enters the blood system. Yet here, it is being directly injected into the body. What happens to this sucrose when it enters the blood system, and why choose sucrose rather than the more standard glucose (dextrose)? Overleaf V2 - How to get BBL File? Using Through to evaluate complex expressions What is the acceptable similarity in a mathematics PhD dissertation when checking by Turnitin? I have checked the originality of my PhD thesis in mathematics using . The similarity was 31%. Is this percentage acceptable by most committees? Only squares instead of letters and numbers are displayed in my calculator and other apps in Ubuntu 18.04 I don't know what I did wrong in my Ubuntu 18.04 OS. For some reason some of my apps look like this:    This also happens to other gnome apps like pdf-reviewer and Logs. Window title, menu bar etc. are all blank, display only squares.  *Problem solved: I downloaded Google Fonts, saved them in a new folder, they can be applied system-wide, but after I did some font settings using Google Fonts it didn't work. I changed the font of Interface with Tweaks-Tool, that was what causing the problem. Equidistant points across Bezier curves Why do I get "Required key not available" when install 3rd party kernel modules or after a kernel upgrade? Show that every prime $p>3$ is either of the form $6n+1$ or of the form $6n+5$ Show that every prime $p&gt;3$ is either of the form $6n+1$ or of the form $6n+5$, where $n=0,1,2, \dots$ I'm trying to make a page where a user provides an ID of a attachment and the site will set the headers and deliver that file instead of a 404 page. so /download/1754 would lookup the attachment with that Id and output it for viewing/download depending on the file type.  I just can't think of a wordpress friendly way to do this from inside a plugin. I considered using add_rewrite_rule but couldn't see a good way around it, also considered checking $_SERVER['REQUEST_URI'] to deliver the content before any HTML but then I'd have to stop the page from rendering a 404 and I was not sure of a Wordpress friendly way to do this.  My current idea was to have my plugin make a download page, assign a template and have that template run the logic instead of my plugin class. while I have used this before for another situation it was very messy as I had to write a lot of code to force users to be unable to update or edit the file and recreate/delete it on activation.deactivation. so ideally I'd like to avoid that.