public class Course {      public static void main(String[]args) {         String name="",course="",marks="";         System.out.println("Enter the name");         name=System.console().readLine();         System.out.println("Enter the course");         course=System.console().readLine();         System.out.println("Enter the marks");         marks=System.console().readLine();         System.out.println("the Name is"+name);     } }   But it works fine if compiled with cmd
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?
Why do video cables (DVI, VGA) still screw in? We were discussing Kirchoff's theorem on blackbody radiation in class today and the equation was: $$e_{f}= J(f,T)$$  $e_f$ was defined as power per unit area per unit frequency. What does per unit frequency refer to here? I know what per unit time means but don't understand 'per unit frequency'. To friend vs. to befriend What does a "CALLBACK" declaration in C do? I was looking through some code from the  library and came across a function declared like this:  LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)   Now, I'm a Delphi coder.  No hablo C muy bien, senor.  But I remember enough syntax from my college courses to read it like this:  Function name is WndProc.  Argument list is pretty self-explanatory.  Function return type is LRESULT.  But what in the world is that "CALLBACK" doing there?  In Delphi, any function can be used as a callback; you just need to pass the right type of function pointer.  Is there any particular reason why C doesn't work that way?  Or does it mean something different? Why is $\infty \cdot 0$ not clearly equal to $0$? I did a bit of math at school and it seems like an easy one - what am I missing?  $$n\times m = \underbrace{n+n+\cdots +n}_{m\text{ times}}$$  $$\quad n\times 0 = \underbrace{0 + 0 + \cdots+ 0}_{n\text{ times}} = 0$$  (i.e add $0$ to $0$ as many times as you like, result is $0$)  So I thought an infinite number of $0$'s cannot be anything but $0$? But someone claims different but couldn't offer a reasonable explanation why. Google results seemed a bit iffy on the subject - hopefully this question will change that. Windows 10 language bar hot keys are reseted to (none) after locking I have 3 different keyboard layouts set up on my laptop and use Ctrl+Shift+[1-3] key combination to switch between them.  Like that:    However, after locking and unlocking Windows (with a password), these hotkeys don't work anymore and key sequence is rolled back to (None):    Signing out from Windows or rebooting the laptop sets everything back to normal, until lock/unlock again.  I think this behaviour is related to the usage of the same hotkeys in File Explorer - to switch view (Extra large icons/Large icons/Medium icons accordingly). After the lock/unlock switch view starts working again.  Seems like File Explorer overrides language bar hotkeys after the unlocking.  How can I disable this functionality? Completely disabling Ctrl+Shift+number functionality in File Explorer will do, however I can't find anywhere on the internet how to do it.  Any ideas or help appreciated! Subset of a finite set is finite We define $A$ to be a finite set if there is a bijection between $A$ and a set of the form $\{0,\ldots,n-1\}$ for some $n\in\mathbb N$.  How can we prove that a subset of a finite set is finite? It is of course sufficient to show that for a subset of $\{0,\ldots,n-1\}$. But how do I do that? Can you maintain concentration on a spell from another plane? What's the use/meaning of the @ character in variable names in C#? I discovered that you can start your variable name with a '@' character in C#.  In my C# project I was using a web service (I added a web reference to my project) that was written in Java. One of the interface objects defined in the WSDL had a member variable with the name "params". Obviously this is a reserved word in C# so you can't have a class with a member variable with the name "params". The proxy object that was generated contained a property that looked like this:  public ArrayList @params {     get { return this.paramsField; }     set { this.paramsField = value; } }   I searched through the VS 2008 c# documentation but couldn't find anything about it. Also searching Google didn't give me any useful answers. So what is the exact meaning or use of the '@' character in a variable/property name? In C#, what makes a field different from a property, and when should a field be used instead of a property? Finding the limit of $(1-\cos x)/x^2$ $$\lim _{x \to 0}{1-\cos x\over x^2}={2\sin^2\left(\frac{x}{2}\right)\over x^2}={\frac{2}{x^2}\cdot {\sin^2\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)^2}}\cdot\left(\frac{x}{2}\right)^2$$  now $$\lim_{x \to 0}{\sin^2\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)^2}=\left({\sin\left(\frac{x}{2}\right)\over \left(\frac{x}{2}\right)}\right)^2=1^2$$  So we have $$\frac{2}{x^2}\cdot \left(\frac{x}{2}\right)^2=\frac{2}{x^2}\cdot \left(\frac{x^2}{4}\right)=\frac{1}{2}$$  Are the moves right? What original Dr Who episodes are left when not watching unfinished stories? Given $S \in B(Y^{*}, X^{*})$, does there exist $T\in B(X,Y)$ such that $S=T^{*}$? How can I share a directory with an another user? I don't want the shared folder to be accessible by anyone on the system, I want it to be accessible just to a restricted set of users.  How to I do that? If $f^2$ is an analytic function then so is $f$ I want to show the following:  If $f(z) $ is a continuous  function on a connected open subset of the complex plane and $f(z)^2$ is an analytic function, then $f(z)$ is analytic.  Clearly if $f(z) \neq 0$ then $$\frac{f(z+h)-f(z)}{h}=\frac{f(z+h)^2-f(z)^2}{h}.\frac{1}{f(z+h)+f(z)}$$  which shows $f^\prime(z) $ exists if $f(z)\neq0$.  What do I do when $f(z) =0$? "The package lists or status file could not be parsed or opened" My advisor wants me to include a name of someone who has no contribution to the paper My first advisor wants me to include my second advisor's name in a paper that I worked on before she (2nd advisor) came along.   Should I include her name even though she didn't do anything in that paper? I don't think she even read it. My screen has 1280 x 1024 resolution. But unfortunately, rightmost belt of 200 pixels is damaged and unable do display any image.  How can I set that the Xorg will treat my screen as 1080 x 1024 device?  Now I have tried:  Virtual 1080 1024 Viewport 0 0   It doesn't work right - image is scaled to fit vertically, and horizontally I can pan with the mouse. Why is the Descriptor not getting called when defined as instance attribute? I have a Dell N5110 laptop with integrated Nvidia GeForce GT 525M and an Intel HD Graphics 3000 card; My problem is the default card is the Intel one, and it provides a very bad performance with Windows 8. So can I force to use the Nvidia one all the time including "Desktop Windows Manager" ?