childEventListener throws nullPointerException
What is a NullPointerException, and how do I fix it?
How to determine equality for two JavaScript objects? 10 servers to administer and I'm a history major Through reasons that don't warrant exhaustive discussion, I find myself in charge of 10 servers:   A domain controller-~500 hosts/~350 users IIS web server-This is where we make our money SQL server-The crown jewels Exchange server Linux box for data entry AV server Backup server A few others tossed around   The company where I work believes everybody is replaceable and therefore believes they can pay a minimum wage for any position. The IT manager and Sysadmin quit recently and I think I was the only person who did not take a big step backward when the call went out for volunteers. This also explains why someone with my background is in this position. That is the reality, as much as I wish it otherwise.  What are the things I should be doing to keep those systems running? There is no written procedure left behind and I crammed the A+ and Network+ certs in the last two months but that leaves me with some theory and no practical experience.  I am in the process of teaching myself powershell but from here to there is a long way. I have no scripting or programming experience.  What tasks should I be performing? What practices should I implement?  I understand I am probably hosed but a lifeline to get me through would be helpful. De Rham Cohomology of the tangent bundle of a manifold I would like to compute the de Rham cohomology of the tangent bundle $TM$ of a manifold $M$. It seems to me that we can just homotopy each fibre to a point, and that this would give a homotopy equivalence between $TM$ and $M$. Since de Rham cohomology is a homotopy invariant, this would imply that $H^*_{\text{dR}}(TM) \cong H^*_{\text{dR}}(M)$.     Is it always true that the tangent bundle of a manifold is homotopic to the manifold itself by the homotopy of each fibre with a point? Quantum information references I would like to sell my Macbook Pro, but I want to make sure that there is no way to retrieve the deleted data from my SSD. Is there a way to completely delete all files on a hard drive so that even a forensic expert cannot recover anything? Highlight the difference between two strings in PHP What is the easiest way to highlight the difference between two strings in PHP?  I'm thinking along the lines of the Stack Overflow edit history page, where new text is in green and removed text is in red. If there are any pre-written functions or classes available, that would be ideal. How does the bounty system work? Last minute flight bookings - better to book online or at the airport? We had , which covered ground on what happens to flight prices over the period.  What I'm interested to know is if I had to fly out at short notice, say within 1-2 days, then am I better off booking within that 1-2 day gap online, or am I better off trying my luck directly at the airport (as long as I'm willing to wait at the airport) for a cheaper price? Is there any truth to rumours that airlines sell tickets at cheaper prices at the airport right before flights to fill empty seats or is that a myth? Is "from where" grammatically equivalent to "from which"? Someone from Mars is called a Martian. Someone from America is called an American. Someone from Europe is a European. Someone from Hyrule is a Hyrulean.  We are not far from colonizing other planets, let alone Earth's only moon. Obviously you wouldn't call someone from the moon a lunatic right? What if you are on Mars? What would I call a foreigner from Earth? Earthean doesn't sound right. Many C++ books contain example code like this...  std::cout &lt;&lt; "Test line" &lt;&lt; std::endl;   ...so I've always done that too. But I've seen a lot of code from working developers like this instead:  std::cout &lt;&lt; "Test line\n";   Is there a technical reason to prefer one over the other, or is it just a matter of coding style? We are given two independent standard normal random variables $X$ and $Y$. We need to find out the M.G.F of $XY$.  I tried as follows : \begin{align} M_{XY}(t)&amp;=E\left(e^{(XY)t}\right)\\&amp;=\int_{- \infty}^{\infty}\int_{- \infty}^{\infty}e^{(XY)t}f_X(x)f_y(y)dxdy \\ &amp;=\dfrac{1}{2\pi}\int_{- \infty}^{\infty}\int_{- \infty}^{\infty}e^{(xy)t}e^{\frac{-x^2}{2}}e^{\frac{-y^2}{2}}dxdy \\ &amp;= \dfrac{1}{2\pi}\int_{- \infty}^{\infty}\int_{- \infty}^{\infty}e^{-\dfrac{(x-ty)^2}{2}}e^{\dfrac{-t^2y^2}{2}}e^{\frac{-y^2}{2}}dxdy \\ &amp;= \dfrac{1}{\sqrt{2\pi}}\int_{- \infty}^{\infty}e^{\dfrac{-t^2y^2}{2}}e^{\frac{-y^2}{2}}dy \\ &amp;= \dfrac{1}{\sqrt{2\pi}}\int_{- \infty}^{\infty}e^{-y^{2}(\frac{1}{2}+t^2)}dy \\ &amp;= \dfrac{1}{\sqrt{1+2t^2}} \end{align} Is this correct ? What's with the Japanese SO's stats? I took this screenshot just now, and  about the new . I refreshed the page, went back, and nothing changed.    And, here's what I find odd:  It clearly isn't almost 2014 years old. That's more likely when it was started.  How can there be 8.7 questions a day, while there are 0 visits a day? That's kind of impossible.   I'm hoping here that it's not just me. I know very limited Japanese, not even enough to hold a conversation with a toddler. I'm merely observing. Sort a Map by values I am relatively new to Java, and often find that I need to sort a Map&lt;Key, Value&gt; on the values.  Since the values are not unique, I find myself converting the keySet into an array, and sorting that array through array sort with a custom comparator that sorts on the value associated with the key.  Is there an easier way? Do I need a visa for a connecting flight to Japan? I'm going to the Philippines this October and would like to layover in Japan. I found a reasonably priced ticket with a 15-hour layover to Haneda, however, I have to transfer to Narita. Do I need a visa since I'm going to have to stay at a hotel and ride a bus to travel to Narita airport? Thank you! What species of insect is this? I saw this insect near a beach in Corsica France: Functional Analysis. Continuous extensions of linear functionals. I would like to show that a continuous functional on a subspace $W$ of a normed space $(V,\|\cdot \|)$ has a unique continuous extension to $V$ iff $W$ is dense in $V$.  I have proved $(\Leftarrow$). But the converse is currently eluding me! Help would be much appreciated! Excessive water when cooking scallops This is partly a continuation of  question, since that one was already closed, but my question is about a specific problem encountered the last time I cooked scallops.  I got the pan up to a reasonable temperature and put the scallops in, and as they were cooking, TONS of water came out of the scallops and filled the pan.  I poured it out, continued cooking, and more water came out.  Several iterations later, I thought they were done, but they were still very raw inside, so we ended up tossing the batch (it definitely wasn't sushi grade).  Where did all the liquid come from, and is there any way to avoid that the next time? I wasn't forcing myself to say anything, or/nor trying to be funny.   "Or" sounds more grammatically correct to me. But "nor" has more Google results. So I'm confused. How would you explain why $e^{i\pi}+1=0$ to a middle school student? Hi I was asked by a friends child who is in middle school why $e^{i\pi}+1=0$. Now I couldn't think of a way to explain it so he would understand. Albert Einstein once said “If you can't explain it simply, you don't understand it well enough” so how would I explain it.