Here is my code to read a text file line per line.       ArrayList&lt;Student&gt; studentCollection = new ArrayList&lt;Student&gt;();     BufferedReader in = null;     try {         in = new BufferedReader(new FileReader("StudentAnswers2.txt"));         String read = null;         while ((read = in.readLine()) != null)          {             read = in.readLine();             String[] splited = read.split(",");             int[] answersTrans = new int[20];              for(int i = 0; i &lt; 20; i++)             {                 answersTrans[i] = Integer.parseInt(splited[i+3]);              }                        studentCollection.add(new Student(splited[0], splited[1], splited[2], answersTrans));                           }   Context: I am trying to set each comma separated value as fields of a List of Student objects ( one line per Student). The first 3 values need to go in as String parameters, and the following 20 values go in as one int[] array.  Here's the content of the txt file:        C97288501,Byrne,John,0,3,3,0,2,4,0,1,4,5,0,3,3,1,2,4,2,0,4,5   D11255403,Smith,Eileen,1,3,2,0,4,3,1,4,5,0,3,3,1,3,4,5,0,5,4,0   C06623662,Doyle,Mary,1,4,3,3,2,2,1,1,4,5,3,3,3,5,2,4,2,5,4,5   C02887223,Radecki,Jason,2,4,3,0,2,2,4,1,0,2,3,3,5,0,4,4,0,4,0,5   D11123581,Hanley,Nora,1,0,2,2,3,0,0,1,5,4,3,3,0,3,2,4,0,5,4,4
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?
Refer to the "name" of an equation, while a List of Equations is generated using these names Proofs using theorems instead of axioms I'm not sure how to prove these basic theorems in propositional calculus. Instead of using the standard axioms, we're supposed to use:   Deduction Theorem (if $\Phi, \alpha \vdash \beta$ then $\Phi \vdash \alpha \to \beta$),  Reductio (if $\Phi, \alpha \vdash \, $, then $\Phi \vdash \lnot \alpha$), Cut Rule (if $\Phi \vdash \alpha$ and $\Psi, \alpha \vdash \beta$ then $\Phi \cup \Psi \vdash \beta$),  Inconsistency Effect (if $\Phi \vdash \, $, then $\Phi \vdash \beta$ for every formula $\beta$), and  the Principle of Indirect Proof (if $\Phi, \lnot \alpha \vdash \, $, then $\Phi \vdash \alpha$),    as all the axioms can be deduced using these theorems.  I don't really know how to start the proofs without using the axioms:  i) prove that $\lnot(\alpha \to \beta) ⊢ \alpha$  ii) prove that $\lnot\alpha \vdash \alpha \to \beta$  Any suggestions on how to start these proofs or any insight at all would be greatly appreciated!  Thanks! How can I test two static methods (one invokes the other) with PowerMockito? Determine number of pages in a PDF file What algorithm is used in linear regression? Please provide a mobile-optimized captcha page Filtered Questions Asked By Accepted Answer/ No Accepted Answer I think it's helpful if we can go to a page and view all our own questions that   Does not have an accepted answer, and/or Does not have an answer yet.   The reason I asked for them is because, I sometimes need to review through all the questions, and pick those that don't have proper answers so that I can perform further operations on them ( such as offering a bounty, or accept an existing answer). Suppose that $f$ is analytic on a close curve γ. Prove or disprove $\int_\gamma \overline{f(z)}f'(z)dz$ is purely imagine. Suppose that $f$ is analytic on a close curve γ. Prove or disprove   $$\int_\gamma \overline{f(z)}f'(z)dz$$  is purely imagine.  I know that $f$ is analytic on a close curve, then   $$\int_\gamma f(z) dz=0$$  I tried an example with $\gamma =e^{it}$ with $0\leq t\leq 2\pi$, I often get the real part of the integral equal zero.  I tried let $f=u+iv$ so $f'=u_x+iv_x$. Since $f=u+iv$, $\overline{f}=u-iv$  $$\overline{f(z)}f'(z)=uu_x+vv_x+i(uv_x-vu_x)$$  But this doesn't get me anywhere. Any help would be greatly appreciated. Opposite of "straight talk" I'm interested in quantum mechanics book that uses high level mathematics (not only the usual functional analysis and the theory of generalised functions but the theory of pseudodifferential operators etc, certainly the modern mathematics). If there isn't something similar please give me a reference to the book that is strictly supported by mathematics (given a set of mathematically descripted axioms author develops the theory using mathematics as a main tool). How do I move Steam games to a new computer without re-downloading them? I have just bought a new computer and I have everything migrated over except for my Steam games.  I looked in Program Files/Steam/ and I found a folder full of the games I have downloaded, but I do not know if it is safe to just copy these folders from one computer to another (seeing as a lot of other applications will not work if you do this), or is there another recommended way?  I don't really feel like re-downloading all my games. I don't have the time nor bandwidth to download 20GB over a 1.5mbps connection.  Is it possible to contact Valve and get a disk with the games on it? Reset lightning:input textbox Field Value to Null I am trying to create a button which will update a field value to null (RESET it). However, it's not working and not even giving any error. So when I click on the button, nothing happens.  lc.cmp:  &lt;aura:attribute name="myObj" type="Account" default="{'SObject':'Account'}"/&gt; &lt;lightning:input type="text" name="accountPhn" label="Enter Account Phone" value="{!v.myObj.Name}"/&gt; &lt;lightning:button label="Reset" onclick="{!c.resetMe}"/&gt;   lc.js:  resetMe : function(component, event, helper) {         //alert("Called");         component.set("v.accountPhn","");     }   Appreciate help around this. Adding Grids in Project Manager of QGIS I am using QGIS 3.12. I am new to QGIS after having worked with ArcGIS Desktop for a while. I am having issues with adding a grid to my project. I am using CRS ESPG:3587 WGS 84 / Pseudo-Mercator and noticed that the grid is showing the wrong coordinates and have included the parameters I have set for the grids. What is the scientific name of this evergreen plant? This plant is found in India. It is an evergreen plant. Would love to know the scientific name. What is the difference between sourcing ('.' or 'source') and executing a file in bash? What's the difference between executing a script like this:  ./test.sh  and executing a script like this:  . test.sh?  I tried a simple, two-line script to see if I could find if there was a difference:  #!/bin/bash ls   But both . test.sh and ./test.sh returned the same information. What is "it" in the following sentence: It is clear that Bob likes doughnuts RegEx match open tags except XHTML self-contained tags How good is it for SEO if you have a widget that lives on other sites? I made a widget that would ideally live on other sites.  Here is an example:   I guess since the widget would link back to me, it would be an SEO boost for my site.  Is that correct?  Or would it be just an SEO boost for that particular URL?  If it is just an SEO boost for the particular URL, it does me little good since that page does not link to any of my other pages.  Am I thinking about this correctly?  How are these things typically handled so that there is  a benefit to my site's SEO? "batch" tag turns into "batch-file" Can someone help with an explanation and some references, in order to understand the nature of return pulses within a LiDAR system.