When I call up a method from the other class, it returns null. I'll just show you my code below  class One{     Two two;     oneMethod(){       String str = "";        two.twoMethod(str);       S.o.p("Str in One class is " + str);       }   }   class Two{    String twoMethod(String str){       str = "From Two class";        S.o.p("Str in Two class is " + str);        return str;     }  }   The output looks like: Str in One class is ___ // meaning null  Str in Two class is From Two class  My understanding about this is, after calling twoMethod(), the str with which is initially null will now be overriden with the new str value "From Two class". Now when we print str in One class, it should be the same with what is printed in the Two class. That's how I understand the flow.   Did I miss any concept / rule about passing Strings? Any feedback is appreciated. Thanks!
I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?
Why does the inverse of the Hilbert matrix have integer entries? Can't login with Google on recently released iPhones and iPads I just switched from an iPhone 7 to an iPhone XR (both are on latest iOS version available).  When I try to login into the Stack Exchange app with my Google account it says:     Request failed   Could not perform this request with your account. Please try logging   back in. If this persist, let us know on meta.   this happens consistently.  I have 2FA enabled on my Google account if it matters.  Is this a known bug? I am working on an iGoogle-like application. Content from other applications (on other domains) is shown using iframes.   How do I resize the iframes to fit the height of the iframes' content?  I've tried to decipher the javascript Google uses but it's obfuscated, and searching the web has been fruitless so far.  Update: Please note that content is loaded from other domains, so the  applies. How do I show that all continuous periodic functions are bounded and uniform continuous? how to sort by the day of the week? I have two files.  file1:  Dave 734.838.9800   Bob 313.123.4567   Carol 248.344.5576   Mary 313.449.1390   Ted 248.496.2204   Alice 616.556.4458      file2:  Bob Tuesday   Carol Monday   Ted Sunday    Alice Wednesday   Dave Thursday     Mary Saturday     I merged the two files.  file3 should look like this:  Name      On-Call     Phone   Carol     MONDAY      248.344.5576   Bob       TUESDAY     313.123.4567   Alice     WEDNESDAY   616.556.4458   Dave      THURSDAY    734.838.9800   Nobody    FRIDAY      634.296.3356   Mary      SATURDAY    313.449.1390   Ted       SUNDAY      248.496.2204     But I cannot get the weekdays to be in order. How do I go about doing that? Best way to list files in Java, sorted by Date Modified? I want to get a list of files in a directory, but I want to sort it such that the oldest files are first.  My solution was to call File.listFiles and just resort the list based on File.lastModified, but I was wondering if there was a better way.  Edit: My current solution, as suggested, is to use an anonymous Comparator:  File[] files = directory.listFiles();  Arrays.sort(files, new Comparator&lt;File&gt;(){     public int compare(File f1, File f2)     {         return Long.valueOf(f1.lastModified()).compareTo(f2.lastModified());     } }); What can a wizard take instead of a familiar at 1st level? The familiar is brilliant feature for a wizard, but not for a prestige multiclassing one. Such a wizard stops upgrading his familiar once getting off the main road. So if he still wants to utilize his familiar, he should take the obtain familiar feat, but this would made the basic familiar feature redundant.  So what options can a wizard take instead of gaining a familiar at 1st level? How to get a JavaScript object's class? I have a PostGIS database and have successfully consumed a table into GeoServer and published a WFS.  Are there REST endpoints available for these WFS' akin to ESRI's feature services?  How are parameters to be constructed? What does "causally connected" or "causes" really mean? In a different thread, a user stated the following about events preceding or following other events:     However, if the two events are causally connected ("event A causes event B"), the causal order is preserved (i.e. "event A precedes event B") in all frames of reference.   My question is what does "causally connected" really mean? What does "causes" mean? Further, given that we know that we can have instantaneous effects in typical quantum processes (e.g. flip the polarizer, effect on another a reading light years away, even though we cannot transmit useful information with this), does that not constitute "causing" for the purpose of this statement? If $u$ is harmonic and bounded in $0 < |z| < \rho$, show that the origin is a removable singularity This is a reworking of a previous question  which was marked as a duplicate. Some nice folks have referred me to solutions to similar problems. I still have a couple of questions, since one of the solutions used the Poisson kernel, which is not the desired solution in the text, because the Poisson kernel has not been introduced yet. The other solutions were for problems that were similar, but whose solutions were only partially applicable, as I understand them.  I'm working on a problem from p. 166 of Lars Ahlfors' Complex Analysis:     If $u$ is harmonic and bounded in $0 &lt; |z| &lt; \rho$, show that the origin is a removable singularity in the sense that $u$ becomes harmonic in $|z|&lt;\rho$ when $u(0)$ is properly defined.   My Solution So Far:   Here's what I've got for a non-Poisson kernel solution: We want to find a harmonic conjugate for $u$ in the punctured disk, and then we can apply big Picard to show that $0$ is a removable singularity. The problem is that the punctured disc is not simply connected.   If we take $\sigma = (u \circ \exp)(z): L \to \mathbb{C}$, where $L$ is the left half-plane, now we have $\sigma$ harmonic, and defined in a simply connected set $L$, so it has a harmonic conjugate $\tau$. Now we wish to take $v = (\tau \circ \log):\{0 &lt; |z| &lt; \rho\}\to \mathbb{C}$, but in order to do so we need $\tau$ to be $2\pi i$-periodic. This is where my proof breaks down.  One of the similar problems which readers referred me to used the following strategy: note that since $\sigma$ is $2\pi i$-periodic, and $\sigma, \tau$ satisfy the Cauchy-Riemann equations, we have that $\nabla\tau(z) = \nabla\tau(z + 2 \pi i)$ for all $z\in L$, or in other words, $\tau(z) - \tau(z+2\pi i)$ is a constant function, say, equal to $\alpha \in \mathbb{R}$. Then, the solution suggests, we can set $$g(z) = u + iv - \frac{c}{2\pi}z,$$  in order to make $g$ $2\pi i$-periodic, and then we can use $(g\circ \log)$ on $\{0 &lt; |z| &lt; \rho\}$. But the reason why this won't work for my purposes is: now we have changed $u$! On the other hand, we can't simply subtract $\frac{c}{2\pi}\Im{(z)}$, and try to leave $u$ untouched, because now $g$ is not analytic. How can we get around this?  Another strategy entirely might be to try to use the mean-value property. Ahlfors discusses that a lot in the preceding section, and his main example is the punctured disc. Since $u$ is harmonic, we know that the average over circles centered at zero is a constant... Autofill feature isn't iterating numbers properly when using the AVERAGE() formula in Microsoft Excel When I input [asdf][lisp] into the search field on , without being logged in, only one tag remains. Is it broken? What would be the Slater's determinant representation for an excited state? Setup  Introducing this spinorbital notation:  \begin{align} \Psi_1=\chi_{(r1)}\alpha_{(\omega1)}  = 1 \\ \Psi_1=\chi_{(r1)}\beta_{(\omega1)}  = \bar{1} \end{align}  and the Slater's determinant, for a system of two electrons, is:  \begin{align} |\Psi\rangle = \frac{1}{\sqrt{2}} \Big|  \begin{array}{cc} 1 &amp; \bar{1}  \\ 2 &amp; \bar{2}  \\ \end{array}  \Big| = \frac{|1\bar{2}\rangle-|\bar{1}2\rangle}{\sqrt2} \end{align}  Question  Based on the example, what would be the Slater's determinant representation for an excited state like $\Psi_a^r$ (i.e. with parallel spins like: $|\bar{1}\bar{2}\rangle$) and $\Psi_{ab}^{rs}$ (feel free to use any number) ? I am wondering whether there is any difference between a gerund acting as subject and an infinitive acting as a subject. Hydraulic Disk brake piston not fully retracting My front disk brake's piston doesn't fully retract.  While I can ride the bike, the brake is slightly rubbing.  (IE, if I just spin the wheel with my hand, it'll go around about one and a half times and then stop.) It's definitely slowing me down.   If this fixable?  The advice I got was that it's not worth the trouble and to buy a replacement set.  The current brakes are Avid Juicy 7s that are about 7 years old Identifying a short story about advertising I am compiling a program which requires boost-thread-mt library. I have installed libboost-all-dev using sudo apt-get install libboost-all-dev but compiler says that it cannot find boost-thread-mt library. Is this library in some other package? Please guide me what i need to install for this. How to compare (probability) predictive ability of models developed from logistic regression? I know some well-known measures are $c$ statistic, Kolmogorov-Smirnov $D$ statistic. However, as far as I know, those statistics take into account only of the rank order of the observations, and is invariant under changing the intercept of the logistic regression model (e.g. in oversampling-correction exercise).  In my current application, I need to depend on the accuracy of the logistic regression to predict probability of event. I know only of qualitative way of assessing models for probability prediction ability, namely by plotting "QQ-plot" of the actual vs predicted probability of event:   Score the validation dataset using the developed model. Rank the observations according to the predicted probability and group into $n$ buckets according to their rank of predicted probability. (First 1/n would go to the first bucket, next 1/n would go to the next ...) Calculate the average predicted and actual probability of Event for each bucket. Create a scatter plot of Predicted vs Actual - one point for each bucket.   I am wondering:   Is the "Q-Q plot" I mentioned above a legitimate way to assess predictive performance of models developed from logistic regression? If so, where may I find more reference for that? Is there any known quantitative way to assess the probability prediction ability of this kind of model? Create WiFi hotspot on ubuntu Although many questions have already been asked regarding WiFi hotspot, I didn't get any of the solutions working for me.  I connect to the Internet using a 3G Dongle of Huawei 3772 (Vodafone). The connection type is Mobile Broadband connection. I have to share this Internet connection with my other devices like mobile phones and laptops.  How can I create a WiFi hotspot connection for this connection.  I am using Ubuntu 12.04 LTS.  I would like to note that I have already tried some help links from Ubuntu but, they are so confusing that I could not understand them.