Whenever I click to the news it crashes, below is LOGCAT  java.lang.NullPointerException: Attempt to invoke virtual method 'long java.util.Date.getTime()' on a null object reference                                                                                     at com.jimdo.saifstudios.lynknews.Adapter.ListNewsAdapter.onBindViewHolder(ListNewsAdapter.java:105)                                                                                     at com.jimdo.saifstudios.lynknews.Adapter.ListNewsAdapter.onBindViewHolder(ListNewsAdapter.java:70)  ListNewsAdapter  class ListNewsViewHolder extends RecyclerView.ViewHolder implements  View.OnClickListener {  ItemClickListener itemClickListener;  TextView article_title; RelativeTimeTextView article_time; CircleImageView article_image;  public ListNewsViewHolder(View itemView) {     super(itemView);     article_image =  (CircleImageView)itemView.findViewById(R.id.article_image);     article_title = (TextView) itemView.findViewById(R.id.article_title);     article_time = (RelativeTimeTextView)  itemView.findViewById(R.id.article_time);      itemView.setOnClickListener(this); }  public void setItemClickListener(ItemClickListener itemClickListener) {     this.itemClickListener = itemClickListener; }  public void setArticle_title(TextView article_title) {     this.article_title = article_title; }  public void setArticle_time(RelativeTimeTextView article_time) {     this.article_time = article_time; }  public void setArticle_image(CircleImageView article_image) {     this.article_image = article_image; }  @Override public void onClick(View view) {     itemClickListener.onClick(view,getAdapterPosition(),false);  } }  public class ListNewsAdapter extends  RecyclerView.Adapter&lt;ListNewsViewHolder&gt;  { private List&lt;Article&gt; articleList; private Context context;  public ListNewsAdapter(List&lt;Article&gt; articleList, Context context) {     this.articleList = articleList;     this.context = context; }  @Override public ListNewsViewHolder onCreateViewHolder(ViewGroup parent, int viewType)  {     LayoutInflater inflater = LayoutInflater.from(parent.getContext());     View itemView = inflater.inflate(R.layout.news_layout,parent,false);     return new ListNewsViewHolder(itemView); }  @Override public void onBindViewHolder(ListNewsViewHolder holder, int position) {      Picasso.with(context)             .load(articleList.get(position).getUrlToImage())             .into(holder.article_image);     if (articleList.get(position).getTitle().length() &gt; 65)      holder.article_title.setText(articleList.get(position).getTitle().substring(0,65)+"...");     else         holder.article_title.setText(articleList.get(position).getTitle());      Date date=null;     try     {         date = ISO8601Parse.parse(articleList.get(position).getPublishedAt());     }catch (ParseException ex)     {         ex.printStackTrace();     }     holder.article_time.setReferenceTime(date.getTime());      // Set event click     holder.setItemClickListener(new ItemClickListener() {         @Override         public void onClick(View view, int position, boolean isLongClick) {             Intent detail = new Intent(context,DetailArticle.class);             detail.putExtra("webURL",articleList.get(position).getUrl());             detail.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);             context.startActivity(detail);            }     });  }  @Override public int getItemCount() {     return articleList.size(); } }
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?
I'm fitting a multiple linear regression model between 4 categorical variables (with 4 levels each) and a numerical output. My dataset has 43 observations.  Regression gives me the following $p$-values from the $t$-test for every slope coefficient: $.15, .67, .27, .02$. Thus, the coefficient for the 4th predictor is significant at $\alpha = .05$ confidence level.  On the other hand, the regression gives me a $p$-value from an overall $F$-test of the null hypothesis that all my slope coefficients are equal to zero. For my dataset, this $p$-value is $.11$.  My question: how should I interpret these results? Which $p$-value should I use and why? Is the coefficient for the 4th variable significantly different from $0$ at the $\alpha = .05$ confidence level?  I've seen a related question, , but there was an opposite situation: high $t$-test $p$-values and low $F$-test $p$-value. Honestly, I don't quite understand why we would need an $F$-test in addition to a $t$-test to see if linear regression coefficients are significantly different from zero. For valuation rings I know examples which are Noetherian.      I know there are good standard non Noetherian Valuation Rings. Can anybody please give some examples of rings of this kind?    I am very eager to know. Thanks. Do I need to activate the firewall? I only use Ubuntu for a home desktop use? DataGridTextColumn.IsReadOnly seems to be faulty I would like my sections to start on a new page if they do not fit on the current page. In other words:  if a section fits on the current page print it, if it does not fit start printing it on the next page.  I would like this to be done automatically.  \usepackage{titlesec} seems to be the solution, but I can not get it to do the job.   Should it be done with titlesec? how ? Is there a better approach? About the relation between $\int_{0}^{\infty}\frac{\cosh((\alpha-\beta)x)}{(\cosh(x))^{\alpha+\beta }} \,dx$ and $B(\alpha,\beta)$ How do I get from   $$B(\alpha,\beta)=\int_{0}^{1}{ t^{ \alpha -1}  (1-t)^{ \beta -1} \,dt}$$ to:   $$2^{2- \alpha - \beta } \int_{0}^{ \infty}{ \frac{ \cosh (( \alpha - \beta )x)}{( \cosh(x))^{ \alpha + \beta }} \,dx}$$  ? I have tried different change of variables such as $t=1- \frac{1}{ \cosh (x)}$ and got $\int_{0}^{ \infty}{ \frac{ \sinh (x)  ( \cosh (x)-1)^{ \alpha -1} }{( \cosh(x))^{ \alpha + \beta }} \,dx}$ but without success. I don't see the gear button next to the Sign in button at the login screen. I have Nvidia drivers installed (for Nvidia 730 GT card). Ubuntu boots into Xorg as seen from the terminal with echo $XDG_SESSION_TYPE which outputs x11.  How do I switch to Wayland? I noticed an unexpected different line spacing of the titlepage what drives me crazy. The left page is the MWE, the right page without the \\ in front of Name.  \documentclass{scrartcl}  \begin{document}  \centering \Huge \textbf{UUUUUUUU UUUUUUUUU UUUUUUUUUUUUU UUUUUUUUUUUUU} \vspace{\baselineskip}\\ \textbf{UUUUUUUU UUUUUUUUU UUUUUUUUUUUUU UUUUUUUUUUUUU} {\rmfamily\Large \vspace{5\baselineskip}\\Name}  \end{document}     Any idea what causes this? Thanks alot!  Cheers, Stephan Lost space after removing bootcamp So I removed bootcamp and now there is a partition called "free space" that I can't remove.  Here is my output from diskutil list:    Here is the screenshot from disk utility showing the partitions:    And here is the error I get when I try to remove "free space":    Heres the output when I run   sudo diskutil apfs resizeContainer disk0s2 0 Choosing research ideas to include in a statement of purpose Can you overload controller methods in ASP.NET MVC? I'm curious to see if you can overload controller methods in ASP.NET MVC.  Whenever I try, I get the error below.  The two methods accept different arguments.  Is this something that cannot be done?     The current request for action 'MyMethod' on controller type 'MyController' is ambiguous between the following action methods: Prove that $\bigcap_{k = 1}^\infty C_k$ is also compact and connected. Let $X$ be a Hausdorff space and let $C_0 \supset C_1 \supset ...$ be a decreasing sequence of compact connected subsets of $X$.  Prove that $\bigcap_{k = 1}^\infty C_k$ is also compact and connected.  I have the compact part.  Just don't know how to show it is connected. I am sitting inside a closed room with a cement ceiling just above my head. The pressure of the atmosphere is exerted on the ceiling from above(outside). But solid cement not being a fluid does not transport that pressure into my room. But i still feel the atm pressure which has no way to be transported into the room.I do not boil to death or anything. How does this happen? Is being good at mathematic contests necessary to pursue a career in mathematics or physics? I am extremely poor in solving a problem quickly, which leaves me doing badly in olympiads and other contests. But, if I just don’t give up on a problem, no matter how much time it takes, I usually end up solving it. To have a future in mathematics or physics, is it necessary for me to excel at contests, because these days children excelling at contests have an advantage over those who don’t (not complete advantage, but advantage nonetheless)? create mesh then add vertices to it in python Error Updating: izx/askubuntu/ubuntu xenial Release' does not have a Release file I am performing an update and its failing on the following:  The repository 'http://ppa.launchpad.net/izx/askubuntu/ubuntu xenial Release' does not have a Release file..   Running a local Ubuntu server 16.04 Long-distance Mind Trick This image is what's supposed to look like in Edit Mode/Object Mode(although I still can make these screenshots even after the update by pressing F12 which is rendering) but the following is what my donut looks like now in Blender.  It shows no shadows and colors. The only thing I did is updating blender to 2.81 from 2.80. And I don't know what but something seems off with blender. Sometimes I can't click any objects so I just pressed tab and then now it's all clickable. Seems like I was in edit mode, but to me, it looked exactly like object mode. I don't know what is wrong with it. How do I make my colors show up again? Why isn't an upgrade to 20.04 from 18.04 available yet? Integral vanishes on all intervals implies the function is a.e. zero I am having trouble with the following problem:      $f:\mathbb{R}\to \mathbb{R}$ is a measurable function such that for all $a$:   $$\int_{[0,a]}f\,dm=0.$$   Prove that $f=0$ for $m$ almost every $x$ (here $m$ is the Lebesgue measure).    I have no problem proving this for $f$ non-negative, or under the assumption that $f$ is integrable. But the question only assumes that $f$ is measurable and no more.  My idea was the usual thing; we look at the set of points where $f$ is positive and negative and assume one of these has measure greater than zero. Then I wanted to estimate one of these by an open set, look at the integral on the open set and show that it had to be greater than zero, a contradiction. But a key part of this attack is the assumption of the absolute continuity of the integral, which only holds in the case where $f$ is integrable.  Alternatively, if it were integrable one could simply estimate $f$ by a continuous function, where the result is quite obvious.  Ultimately we are going to show that $f$ is integrable, but it is not clear to me how to show this before showing it is zero a.e. So there must be a simpler way. Does anyone have suggestions?