I'm a beginner at programming in Java.  I'm aware of the number of topics on this particular message error but I haven't been able to fix this issue. The error is indicated to be in line 23 in the following code.  I'm aware the problem seems to be linked to null references, but I'm failing to see how my method "Recommander" isn't assigning values to all the references.   public class Recommander{  // predetermined array of series  private String[]  serie= {"Friends S1","Friends S2",      "Friends S6","Friends S7", "Friends S8", "How I met your mother S1",     "How I met your mother S2","How I met your mother S3 ","Castle S3",      "Santa Clarita Diet S1", "Modern Family S1","Modern Family S2",     "Family Guy S6", "The Simpsons S5"};   // array of the purchases of one customer   private int[] profil ;   //number of profiles in the database private int nbProfils = 10 ;   // array of all the profiles from the database and the series available private int[][] records ;  // creation of an instance of the object Recommander  public Recommander() {      for (int k=0;k&lt;=nbProfils-1; k++) {         for (int i=0; i&lt;=serie.length-1;i++) {              records[k][i]= (int) (Math.random())*2 ;          }     }  }   // Display of the series available in store public String affichageSerie() {      String Affichage = "" ;      for (int i = 0 ; i&lt;=serie.length-1; i++) {          Affichage = Affichage + serie[i] +  "\n" ;      }      return Affichage  ; }    }
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?
prove inequality through mean value theorem What is the purpose of JNDI NSString question - rangeOfString method What is a smart pointer and when should I use one? What is a smart pointer and when should I use one? Root of continuous function using Rolle's Theorem $$f(x)= 1 + e^x\cos(x)$$   $$g(x)= 1 + e^x\sin(x)$$      Show that there is at least one root of $g$ between two roots of $f$   How do I start to answer this question and do I need to use Intermediate Value Theorem? How can I make a logo in Adobe Illustrator like the AntiParticle logo below, from ?   It is a large number circles of different, varying sizes, which form the shape of a text character. I've placed a command block making it day all the time. I want to turn it off, but I've lost it. What's the quickest way to find it? Between vs. Among - "Difference [between | among] one thing and other things." Consider the following two versions of a question:1   Version 1: What is the difference in meaning between "[to be] not invited" and similar negation forms?  Version 2: What is the difference in meaning among "[to be] not invited" and similar negated forms?    Personally, I think Version 1 might subtly suggest a Star Topology (see below) with the target sentence "[to be] not invited"at the center.  And Version 2 might subtly suggest a more free-form comparison like the Mesh or Fully Connected, with the target sentence simply "one among many":   Between approx equal "Star" and among approx equal "Fully Connected"?  Don't get me wrong: I do think this is quite subtle, not always applicable, and I don't think anyone would intuit such a "network topology" meaning without further explanation.   So the main question is, are both grammatically correct?  If yes, is there a semantic difference to choose one over another, perhaps as I suggested?  Or does the plurality aspect of between and among trump other semantic and stylistic issues?    1. In my question , another user provided a very helpful edit. However, the change of the word between to among prompted this question. Euclidean domain in which the quotient and remainder are always unique Let $R$ be a Euclidean domain in which the quotient and remainder are always unique. Does it follow that the ring $R$ is either a field or a polynomial ring $F[X]$ for some field $F$? Best way to remove an event handler in jQuery? I have an input type="image". This acts like the cell notes in Microsoft Excel. If someone enters a number into the text box that this input-image is paired with, I setup an event handler for the input-image. Then when the user clicks the image, they get a little popup to add some notes to the data.  My problem is that when a user enters a zero into the text box, I need to disable the input-image's event handler. I have tried the following, but to no avail.  $('#myimage').click(function { return false; }); How to do one-class text classification? I have to deal with a text classification problem. A web crawler crawls webpages of a certain domain and for each webpage I want to find out whether it belongs to only one specific class or not. That is, if I call this class Positive, each crawled webpage belongs either to class Positive or to class Non-Positive.  I already have a large training set of webpages for class Positive. But how to create a training set for class Non-Positive which is as representative as possible? I mean, I could basically use each and everything for that class. Can I just collect some arbitrary pages that definitely do not belong to class Positive? I'm sure the performance of a text classification algorithm (I prefer to make use of a Naive Bayes algorithm) highly depends on which webpages I choose for class Non-Positive.  So what shall I do? Can somebody please give me an advice? Thank you very much! How to make a film in black and white and add color to some objects? How is a movie made to show selective colors. For instance, in  a sister and brother are transported to the universe of an old black and white TV show, and the movie switches to being B&amp;W. Then, as the protagonists cause the inhabitants to have 'real' emotions, like fright, anger, or love, things (people, places, etc.) start having color. In the middle of the movie, many objects are still B&amp;W, yet many more are now colorized.   also used this effect (the whole film was initially shot in full color, and was converted to black-and-white. Colorization is used on certain subjects in a scene), for example.  How is this effect achieved? Is it post-production editing? What techniques might a director employ to do this? Let $y$ be a differentiable function on $\mathbb{R}$. If  $$\lim_{x\rightarrow \infty}(y(x)+y'(x))=0$$ Then how does one show that $$\lim_{x\rightarrow \infty}y(x)=0$$ I'd appreciate some help on this problem. Thanks a lot. How do I know whether to use the definite (the) or indefinite (a, an) article, and when to omit it altogether? I noticed there is a square knob sticking out of my basement wall. Does anyone know what this is? Can't get armature to move mesh! Get variable from PHP to JavaScript I want to use a PHP variable in JavaScript. How is it possible? How does a phonon cause two electrons to attract each other and form a cooper pair? We know that like charges repel each other. But my professor claimed that two electrons can attract each other as well. What he said was that due to screening an electron travelling at some speed won't repel another electron, but that they will, in some cases, attract each other due to weak phonon exchange. What does that mean? What is phonon exchange? Do two electrons really attract each other? VAR/VECM/ARDL optimal lag selection Question 1: Is it necessary to consider AIC and the BIC criteria when selecting the lag for a VAR, VECM or ARDL model OR can I use something else?  Example: Can I pick 12 lags because the model simply produce great results when I do or do I have to use the AIC/SIC criteria?  Question 2: A simple google search tells me that its possible to select lag 4 when quarterly data, 12 when monthly etc. Is that a valid approach ? command to zip multiple directories into individual zip files I have a single directory that contains dozens of directories inside of it.  I'm new to command line and I'm struggling to come up with a command that will zip each sub-directory into a unique sub-directory.zip file.  So in the end my primary directory will be filled with all of my original sub-directories, plus the corresponding .zip files that contain the zipped up content of each sub-directory.  Is something like this possible? If so, please show me how it's done.