import java.awt.Robot; import java.awt.Toolkit; import java.awt.datatransfer.StringSelection; import java.awt.event.KeyEvent;  import org.openqa.selenium.By; import org.openqa.selenium.Keys; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement; import org.openqa.selenium.firefox.FirefoxDriver; import org.openqa.selenium.interactions.Actions; import org.openqa.selenium.support.FindBy; import org.openqa.selenium.support.PageFactory; import org.openqa.selenium.support.ui.ExpectedConditions; import org.openqa.selenium.support.ui.WebDriverWait;  public class EmployeeTest {  @FindBy(xpath="//input[@id='email']") public static WebElement emailIDField;  @FindBy(xpath="//input[@id='password']") public static WebElement passwordField;  @FindBy(xpath="//a[@id='submitButton']") public static WebElement loginButton;  static String subscriptionsAndBillingTabXpath="//a[contains(text(),'Silling')]"; @FindBy(xpath="//a[contains(text(),'Silling')]") public static WebElement subscriptionsAndBillingTab;  public static WebDriver driver;  public static WebDriverWait wait;  public static void main(String[] args) {     // TODO Auto-generated method stub     driver = new FirefoxDriver();      driver.get("http://url.domain.com");      wait.until(ExpectedConditions.visibilityOf(emailIDField));     emailIDField.click();     emailIDField.sendKeys("abc@abc.com");      wait.until(ExpectedConditions.visibilityOf(passwordField));     passwordField.click();     passwordField.sendKeys("xyz");      loginButton.click();      wait.until(ExpectedConditions.visibilityOf(subscriptionsAndBillingTab));     if(driver.findElements(By.xpath(subscriptionsAndBillingTabXpath)).size()!=0)         System.out.println("Login successful!");      else         System.out.println("Failed to login!");     driver.close();  }  }   exception seen is below,  Exception in thread "main" java.lang.NullPointerException     at org.openqa.selenium.support.ui.ExpectedConditions.elementIfVisible(ExpectedConditions.java:227)     at org.openqa.selenium.support.ui.ExpectedConditions.access$1(ExpectedConditions.java:226)     at org.openqa.selenium.support.ui.ExpectedConditions$7.apply(ExpectedConditions.java:213)     at org.openqa.selenium.support.ui.ExpectedConditions$7.apply(ExpectedConditions.java:1)     at org.openqa.selenium.support.ui.FluentWait.until(FluentWait.java:208)     at EmployeeTest.main(EmployeeTest.java:43)
What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?
So, I was just assaulted by a trio of fairly well armed thugs while walking out of Riften. Before attacking me, they informed me that they were 'here to teach me a lesson.'  After dispatching them in due course, I found this on the body of what I can only assume to be the leader, given his vastly superior armaments:   Orgnar is the innkeeper in Riverwood. Now, I admit, I've stolen a fair amount, but I pride myself on having never been caught. My total bounty to date is at zero. So, how did he figure out that I stole something, why is he taking the law into his own hands, and if I go back to Riverwood, am I going to get shanked? Do I use ext4 for all partitions (such as / and /boot)? What are the other formats used for? I'm installing ubuntu onto a new laptop with 24gb SSD and a 500gb HDD. I wanted to put / and swap onto the SSD and /home onto the HDD. Is there anything I shouldn't use ext4 for?  I do not ever intend to dual boot. Ubuntu only. Pandemic, Global Epidemic, Epidemic, Endemic I really want to hear from the experts the definitions of all 4 terms especially whether global epidemic is equivalent to pandemic. Or should this question be directed to the epidemiologist?   Pandemic Global Epidemic Epidemic Endemic   I have Googled the terms and I understand the definition of 1), 3) and 4). In short the definition is based on geographical location and scale of outbreak, Pandemic is an outbreak of disease on a global scale (e.g. HIV). Epidemic is an outbreak of disease on a localised area. Endemic is a disease in a localised area. However, a definition for Global Epidemic is not available online.  Recently, WHO mentioned that "“It is important to put this on the table: this virus(Covid19) may become just another endemic virus in our communities, and this virus may never go away,” WHO emergencies expert Mike Ryan told an online briefing." Isn't covid19 considered a pandemic since it is on a global scale and is spreading rapidly?  Another term that I come across often is Global Epidemic. For example in the WHO website, HIV is listed as Global Epidemic. Does that mean Pandemic and Global Epidemic are the same? Is there a way to set the gnome-terminal title from within the terminal itself without having to right click on the tab. Something like:  active-terminal --title "Foo"   There was a related question previously with an answer that almost lets you do this:  but that doesn't set the gnome-terminal tab title only the window title. "Has/Have/Had" as a main verb and auxiliary verb I need help regarding the use of has/have/had both as a main verb and as an auxiliary verb.  In the sentence below, the word has acts as the main verb. I would normally follow it with the phrase "so do I."        Kenny has a car, and so do I.      On the other hand, the word has in the following sentence acts as an auxiliary verb. I would normally follow it with the phrase "so have I."        Kenny has bought a car, and so have I.      a) Are sentences 1 &amp; 2 above correct? I'm under the impression that so do I is used when has/have/had is the main verb of a sentence, and so have/had I if it's an auxiliary verb in a sentence.  b) Does the verb has/have always need a supporting "auxiliary verb" (either implied or mentioned)? (e.g., Kenny has a car = Kenny does have a car.) Several wands and other magic items in the DMG cite &quot;spellcaster&quot; as an attunement requirement, specifically &quot;requires attunement by a spellcaster&quot; while others list multiple spellcasting classes (e.g., a Staff of Fire &quot;requires attunement by a druid, sorcerer, warlock, or wizard&quot; p. 201). However, all the DMG states in this regard is:  Some magic items require a creature to form a bond with them before their magical properties can be used. This bond is called attunement, and certain items have a prerequisite for it. If the prerequisite is a class, a creature must be a member of that class to attune to the item.¹ (If the class is a spellcasting class, a monster qualifies if that monster has spell slots and uses that class's spell list. [emphasis and footnote added] (p. 136)  The language of the Mage Slayer feat describes a spellcaster as a creature casting or concentrating on a spell.  You have practiced techniques useful in melee combat against spellcasters [...] When a creature within 5 feet of you casts a spell ... [and] When you damage a creature that is concentrating on a spell ... (PHB, p. 168)  From the above, it does not appear that &quot;spellcaster&quot; would necessarily be considered a class or group of classes, so Are characters that can cast spells, regardless of their class(es), considered spellcasters? Or, put another way, Does &quot;spellcaster&quot; (as an attunement prerequisite) mean any creature who can cast a spell or does it mean all classes with the Spellcasting feature? I can think of five particular cases—innate abilities, two subclasses and two feats: High Elves know one wizard cantrip (0-level spell) of their choice. Drow can cast the dancing lights cantrip, 1st-level spell faerie fire and 2nd-level spell darkness. Forest Gnomes know the minor illusion cantrip, and Tieflings can cast the thaumaturgy cantrip and 2nd-level spells hellish rebuke and darkness. Also, many monsters have innate spellcasting abilities, which would trigger the Mage Slayer feat. Starting at 3rd level, both the Eldritch Knight (Fighter Martial Archetype) and Arcane Trickster (Roguish Archetype) gain the ability to cast wizard spells and gain wizard spell slots (potentially) up to 4th-level spells. PHB, pp. 75 &amp; 98. The latter's 17th-level Spell Thief feature also states &quot;you gain the ability to magically steal the knowledge of how to cast a spell from another spellcaster,&quot; (Ibid.) which strongly implies that (at least) the Arcane Trickster is a spellcaster, although neither subclass is specifically listed as a prerequisite for any magic item in the DMG. Eldritch Knight and Arcane Trickster are also found under Multiclassing, Spell Slots in the PHB:  You determine your available spell slots by adding together all your levels in the bard, cleric, druid, sorcerer, and wizard classes, half your levels (rounded down) in the paladin and ranger classes, and a third of your fighter or rogue levels (rounded down) if you have the Eldritch Knight or the Arcane Trickster feature. (p. 164)  With the Ritual Caster feat, a character chooses a spellcasting class (except paladin or ranger) and gains the ability to cast spells of that class with the ritual tag as rituals. The character immediately gets two 1st-level ritual spells of that class and has the potential to (eventually) learn all of the ritual spells of the chosen class. PHB, p. 169. With the Magic Initiate feat, a character chooses a particular spellcasting class (except paladin or ranger) and immediately learns two cantrips and one 1st-level spell from the class with no further advancement. PHB, p. 168. By definition, it seems all of the above would qualify as spellcasters, but I feel spellcaster typically (or maybe traditionally) refers to bard, cleric, druid, paladin, ranger, sorcerer, warlock and wizard.   I believe an exception would be a 13th level or higher Thief (Roguish Archetype) due to the Use Magic Device feature. PHB, p. 97. How to express a polar coordinate for a macro that only accepts space-separated values? \psElectricfield only accepts a coordinate in space-separated values as follows. For example, a charge of -0.1 unit at (-1,0) is written as [-0.1 -1 0]. I have attempted to write in PS notation but it still does not work.  \documentclass{article} \pagestyle{empty}  \usepackage{pst-electricfield,multido} \def\M{2}  \begin{document} \multido{\i=0+30}{12}{% \begin{pspicture*}(-\M,-\M)(\M,\M)     \psElectricfield     [         Q={[-0.1 -1 0][-0.1 1 0][0.1 !\i sin 2 mul \i cos 2 mul]}     ] \end{pspicture*}\newpage} \end{document}   How to express  a polar coordinate for a macro that only accepts space-separated values? How to convert HTML to XHTML? I need to convert HTML documents into valid XML, preferably XHTML. What's the best way to do this? Does anybody know a toolkit/library/sample/...whatever that helps me to get that task done?  To be a bit more clear here, my application has to do the conversion automatically at runtime. I don't look for a tool that helps me to move some pages to XHTML manually. Frequent Write to Non-volatile Memory I am designing a device that automatically adjusts it's physical position as temperature changes. If the device it shut off or power is disconnected the device needs to remember it's last temperature and position. I have the ability to store these values in EEPROM but the problem is the position and temperature could be changing very rapidly. If I were to write the temp and pos to EEPROM after every time they changed that would (1) slow down the firmware a bit, and (2) likely kill the EEPROM after a year or two. So as I see it my options are as follows...  1) use a capacitor/battery to keep the device powered for a short time after power is lost so that I can write the values to EEPROM at that time only. I don't like this because the board is kinda power hungry and this would require a big cap. And I don't have a ton of free space. And I don't want the added cost of a battery and battery holder / or a big cap.  2) use F-RAM instead of EEPROM so that I can write to it trillions of times without wearing it out. I don't like this option because FRAM is quite a bit more expensive than EEPROM and this is for a production product (not just one).  3) Only write the position and temperature every 5 minutes or so. That way I always have a fairly recent position/temp recorded but I am not writing every second so my program is not slowed down and the EEPROM won't die as fast. This seems like my best option.  Does anyone else have any suggestions that I'm not thinking of? There does not exist an entire function which satisfies $f({1\over n})={1\over 2^n}$, what I tried is if possible then define $g(z)=f(z)-{1\over 2^{1\over z}}$ Then $g({1\over n})=0$ and so $g(z)$ is entire and its $0$ set has limit point in it and so $f(z)={1\over 2^{1\over z}}$ which is not analytic at $0$? Please help!  Edit: OOps! the way I defined $g(z)$ that is not entire! could any one give me hint? Mac asking for password for some files when deleting This happens not for all files. When I move or delete some of the files on my external drive Finder will ask for password. Is it due to permission set on these files ? Can I use something like Sudo when running Finder to prevent these pop ups ? The reason I'm asking is that sometimes I leave the mac running to move some files from one disk to another, just to find it on the password prompt a few hours later. Thank you. I'm trying to use arcpy to save an .mxd and am having an issue.  It doesn't matter if I use mxd.save or mxd.saveACopy I get the same error.  I know it doesn't look like I am doing anything w/ it here, but it's just a portion of my code:  import arcpy import arcpy.mapping as map arcpy.env.overwriteOutput = True  env.workspace = r"C:\MGIS\FinalProject2.gdb     mxd = map.MapDocument(r"C:\MGIS\Finalproject2.mxd") df = map.ListDataFrames(mxd)[0]  for df in map.ListDataFrames(mxd): df.scale = 2000000  #Add layers into map document addLayer = map.Layer(OKXcounties) addLayer1 = map.Layer(contourLabelText) addLayer2 = map.Layer(contoursClipLyr) addLayer3 = map.Layer(clipOKXLyr) map.AddLayer(df, addLayer, "AUTO_ARRANGE") map.AddLayer(df, addLayer1, "AUTO_ARRANGE") map.AddLayer(df, addLayer2, "AUTO_ARRANGE") map.AddLayer(df, addLayer3, "AUTO_ARRANGE")  # Add contour Labels for lyr in map.ListLayers(mxd):     if lyr.name == "contourLabelText":         lyr.showLabels = True     if lyr.name == "Contour Features":         lyr.transparency = 100  mxd.saveACopy(mxd)   I get the following error:   Traceback (most recent call last):   File "C:\Python26\ArcGIS10.0\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py", line 312, in RunScript     exec codeObject in __main__.__dict__   File "C:\MGIS\geog485\FinalProject2\mxdtest.py", line 7, in &lt;module&gt;     mxd.saveACopy(mxd)   File "C:\Program Files\ArcGIS\Desktop10.0\arcpy\arcpy\utils.py", line 181, in fn_     return fn(*args, **kw)   File "C:\Program Files\ArcGIS\Desktop10.0\arcpy\arcpy\_mapping.py", line 668, in saveACopy     self._arc_object.saveACopy(file_name) AttributeError: MapDocObject: Unable to save.  Check to make sure you have write access to the specified file and that there is enough space on the storage device to hold your document.   Space is not the issue, I have 60 GB of free space and I've checked the windows properties of the .mxd file.  Read-only box is unchecked and I've "allowed" all permissions for all groups:    Does anyone have any idea how if this is a bug or how I can fix this?  I'm using ArcInfo 10.0 SP4. Windows 10 won't accept Firefox as the default browser We just got a new laptop (ASUS) though we did have a mac.  We are trying to log onto Mojang to download Minecraft and it keeps saying, "The username and password are not recognized."   We have done all the usual procedures; we have reset the password, we are using the email, not the username to sign in, and it looks like the minecraft login servers are working etc. etc.  We quit Minecraft on the old computer and shut off that computer thinking that was the issue.   Still, we can't get onto Mojang.  We are accessing mincraft through firefox and trying to download it to the new computer but we can't get into the account to do that!  What in the world could be the issue? How to truncate a file in C? Changing a CSS rule-set from Javascript Solve $\lim_{x\to 0} \frac{\sin x-x}{x^3}$ I'm trying to solve this limit     $$\lim_{x\to 0} \frac{\sin x-x}{x^3}$$   Solving using L'hopital rule, we have:  $$\lim_{x\to 0} \frac{\sin x-x}{x^3}= \lim_{x\to 0} \frac{\cos x-1}{3x^2}=\lim_{x\to 0} \frac{-\sin x}{6x}=\lim_{x\to 0} \frac{-\cos x}{6}=-\frac{1}{6}.$$  Am I right?  I'm trying to solve this using change of variables, I need help.  Thanks  EDIT  I didn't understand the answer and the commentaries, I'm looking for an answer using change of variables. Prove that $B[x] \cap B[x^{-1}]$ is integral over $B$ Ubuntu 16.04 Jan 3 2018 update causing screen/access issues The server version of Ubuntu does not have the  command. How can I add a  (PPA) to the server without this command?