I am working on a java project right now. I have two main questions that I must know the answers to.  When working with an Object passed through Parameters, does the passed Object work as a pointer to the original Object, as in:   public void DoThis(Object That) {     That.function(10, 100); // Let's just say this raises 10 to the power of 100, I know this function works as it's part of the original Object.     That = new Object(); // I want to know if this changes anything in the original Object or if the passes "That" Object I use is a reference or copy of some sort. }   Another question is that if I set a Local Object equal to another Object that already exists, then set that Object to a different Object or a new Object all together, if it alters the first Object I set it equal to, as in:   public void DoThisOtherThing(Object That, boolean Maybe) {     Object Thing = That.getSub();     if (Maybe)         Thing = Thing.getSub(); // I want to know if this would change That.getSub();     else         Thing = new Object(); // I want to know if this would also change That.getSub(); I would imagine if the other case doesn't, this wouldn't, and vice versa     That.getSub().setValue(Thing.getValue()); }   I am more familiar with C and it's much more straight forward to me. Java has a lot of things handled in the background automatically by the Java Runtime and don't know exactly what it's doing here. I normally don't work with Java, but for this project I am working on, I need to. Thank you in advance! :)
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?
By integration by parts and the substitution $x = \sin t$ we can easily calculate the integral $\int_{0}^{1} \ln (x+ \sqrt{1-x^2})dx$ which equals to $\sqrt{2} \ln (\sqrt{2} +1) -1.$ I’ve tried to use the same substitution $x = \sin t$ to calculate the integral $ \int_{0}^{1} \frac {\ln (x+ \sqrt{1-x^2})}{x}dx,$ which becomes $$ \int_{0}^{\frac {\pi}{2}} \frac {\ln \sin (t+ \frac {\pi}{4})}{\sin t}dt$$ It seems difficult to solve the particular integral. Any help? My computer boots to a black screen, what options do I have to fix it? I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents: How to install Broadcom wireless drivers offline? I have installed Ubuntu alongside Windows 8.1. But the wifi is not working in Ubuntu (perhaps the drivers are not present), which worked fine in windows. Also I cant connect with Ethernet since my laptop does not have an Ethernet port. So is there any way for me to connect to the internet in ubuntu? Edit: Output of the terminal command  lspci -knn | grep Net -A2:  vikram@vikram-Inspiron-11-3148:~$ lspci -knn | grep Net -A2 01:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)     Subsystem: Dell Device [1028:0018]     Kernel driver in use: bcma-pci-bridge vikram@vikram-Inspiron-11-3148:~$    I did what Pilot6 suggested. Here is the output:    vikram@vikram-Inspiron-11-3148:~$ sudo dpkg -i *.deb [sudo] password for vikram:  Selecting previously unselected package bcmwl-kernel-source. (Reading database ... 163804 files and directories currently installed.) Preparing to unpack bcmwl-kernel-source_6.30.223.141+bdcom-0ubuntu2_amd64.deb ... Unpacking bcmwl-kernel-source (6.30.223.141+bdcom-0ubuntu2) ... Selecting previously unselected package dkms. Preparing to unpack dkms_2.2.0.3-1.1ubuntu5.14.04_all.deb ... Unpacking dkms (2.2.0.3-1.1ubuntu5.14.04) ... Setting up dkms (2.2.0.3-1.1ubuntu5.14.04) ... Setting up bcmwl-kernel-source (6.30.223.141+bdcom-0ubuntu2) ... Loading new bcmwl-6.30.223.141+bdcom DKMS files... First Installation: checking all kernels... Building only for 3.16.0-30-generic Building for architecture x86_64 Building initial module for 3.16.0-30-generic ERROR (dkms apport): kernel package linux-headers-3.16.0-30-generic is not supported Error! Bad return status for module build on kernel: 3.16.0-30-generic (x86_64) Consult /var/lib/dkms/bcmwl/6.30.223.141+bdcom/build/make.log for more information. modprobe: FATAL: Module wl not found. update-initramfs: deferring update (trigger activated) Processing triggers for man-db (2.6.7.1-1ubuntu1) ... Processing triggers for initramfs-tools (0.103ubuntu4.2) ... update-initramfs: Generating /boot/initrd.img-3.16.0-30-generic vikram@vikram-Inspiron-11-3148:~$ We are provided with a string A (may contain repeated characters as well ). One needs to make all possible permutations of A , and find out how many pairs of strings chosen from these permutations are not similar.  Two strings are similar if we can make both of them exactly same by carrying out at most 1 swap in each of them .  Example :- if we are provided with string abcd  , then for permutation abcd , the permutations which are not similar to it are bcda , bdac , cadb , cdba , dabc , dcab . Similar is the case for other permuations as well. So overall number of desired pairs are 24*6=144 .  I tried solving it for each possible pair by approach mentioned here     But as the permutations can be large enough , I need a better approach of solving this. Why is the t-test designed for small samples? How to float until on left (or right) page? I have two sideways tables that I want on two facing pages so the reader can turn the entire book and read them both in one turn. For the moment I keep moving them around to keep them on facing pages. Is there a way I can make the first one float until it's on a left page and then place the other one right after? Or perhaps some similar way to automatically get them on the same spread? Show that the Sorgenfrey line does not have a countable basis. Updating global js variable within function and sending updated to HTML document Finding Value of the Infinite Product $\prod \Bigl(1-\frac{1}{n^{2}}\Bigr)$ While trying some problems along with my friends we had difficulty in this question.   True or False: The value of the infinite product $$\prod\limits_{n=2}^{\infty} \biggl(1-\frac{1}{n^{2}}\biggr)$$ is $1$.   I couldn't do it and my friend justified it by saying that since the terms in the product have values less than $1$, so the value of the product can never be $1$. I don't know whether this justification is correct or not. But i referred to Tom Apostol's Mathematical Analysis book and found a theorem which states, that    The infinite product $\prod(1-a_{n})$ converges if the series $\sum a_{n}$ converges.   This assures that the above product converges. Could anyone help me in finding out where it converges to? And,   Does there exist a function $f$ in $\mathbb{N}$ ( like $n^{2}$, $n^{3}$) such that $\displaystyle \prod\limits_{n=1}^{\infty} \Bigl(1-\frac{1}{f(n)}\Bigr)$ has the value $1$? I need to create a metadata-table for all files in a File Geodatabase.   Is it possible to automatically be updated with new filenames, and possibly even metadata (as created in the ArcGIS metadata editor)? A list of inconveniences between quantum mechanics and (general) relativity? It is well known that quantum mechanics and (general) relativity do not fit well. I am wondering whether it is possible to make a list of contradictions or problems between them?  E.g. relativity theory uses a space-time continuum, while quantum theory uses discrete states.  I am not merely looking for a solution or rebuttal of such opposites, more for a survey of the field out of interest. Convergence of an alternating series : $ \sum_{n\geq 1} \frac{(-1)^n|\sin n|}{n}$ Study the convergence of $$\displaystyle \sum_{n\geq 1} \frac{(-1)^n|\sin n|}{n}.$$   I am stuck with this series, we need probably some measure of irrationally of $\pi$, unfortunately I am unfamiliar with this. So here is my attempt :  Let $f(x) = \sum \frac{|\sin{n}|}{n} x^n, |x| &lt; 1$  It's not difficult to compute the Fourier series of $|\sin(x)|$ :  $$ \displaystyle|\sin(x)|=\frac{2}{\pi}-\frac{4}{\pi}\sum_{n=1}^{+\infty}\frac{\cos(2nx)}{4n^2-1} $$  Then Fubini's theorem () works very well (because the previous series converges absolutely at $x$ fixed ) and all calculations made, we find that for all $x\in( -1,1)$:  $$ \displaystyle f(x)=\frac{2}{\pi}\sum_{n=1}^{+\infty}\frac{x^n}{n}-\frac{4}{\pi}\sum_{p=1}^{+\infty}\frac{x^2-2x\cos(p)}{(4p^2-1)(x^2-2x\cos(p)+1)} $$  However, the second sum I have not been able to show the convergence. I feel the series diverge because the following series $$ \displaystyle\sum\frac{1}{p^2\sin^2\left(\frac{p}{2}\right)} $$  diverge because  $0$ is an accumulation point of $\displaystyle (n\sin(n))$ sequence.  Any ideas (for the original series) ? Posting images in chat using drag and drop I think it will be a good idea if there is a drag and drop image posting in chat. User needs to follow many steps to upload an image using upload button. Realtek RTL8723be doesn't have good reception When would you use a WeakHashMap or a WeakReference? The use of weak references is something that I've never seen an implementation of so I'm trying to figure out what the use case for them is and how the implementation would work. When have you needed to use a WeakHashMap or WeakReference and how was it used? After a company has issued shares, why should it care if the value of the shares fluctuate? Since the shares are now publicly traded, if the value fluctuates, that is strictly a transaction between buyer and seller, none of whom are directly related to the company. E.g. if I sell X an iPhone for $100, why should I care if X is selling the iPhone to Y for 1 dollar or 1000 dollars? I have got my $100, so I need not bother. No? Python provides the "*" operator for unpacking a list of tuples and giving them to a function as arguments, like so:  args = [3, 6] range(*args)            # call with arguments unpacked from a list   This is equivalent to:  range(3, 6)   Does anyone know if there is a way to achieve this in PHP? Some googling for variations of "PHP Unpack" hasn't immediately turned up anything.. perhaps it's called something different in PHP? Is it possible that by mutation a human could see infrared or other 'colours'? Incoming light reacts with the several types of cone cells in the eye. In humans, there are three types of cones sensitive to three different spectra, resulting in trichromatic color vision. Each individual cone contains pigments composed of opsin apoprotein, which is covalently linked to either 11-cis-hydroretinal or more rarely 11-cis-dehydroretina.  The opsins (photopigments) present in the L and M cones are encoded on the X chromosome.  A very small percentage of women may have an extra type of color receptor because they have different alleles for the gene for the L opsin on each X chromosome. X chromosome inactivation means that only one opsin is expressed in each cone cell, and some women may therefore show a degree of tetrachromatic color vision. Tetrachromacy is also demonstrated among several species of birds, fish, amphibians, reptiles and insects.  Humans cannot see ultraviolet light directly because the lens of the eye blocks most light in the wavelength range of 300–400 nm.  So, besides above mentioned exceptions, is it possible due to mutations or genetic engineering to see UV or infrared. What kind of mutations should be made or are the changes to be made in the opsines to big to create 'alien' eyes? Soft version of the maximum function? In the book Deep Learning, it says the softmax function is de facto a soft argmax function, and the corresponding soft version of the maximum function is $$\text{softmax} (z)^T z$$ How to understand the latter? Where did the "wheel" group get its name? The wheel group on *nix computers typically refers to the group with some sort of root-like access. I've heard that on some *nixes it's the group of users with the right to run su, but on Linux that seems to be anyone (although you need the root password, naturally). On Linux distributions I've used it seems to be the group that by default has the right to use sudo; there's an entry in sudoers for them:  %wheel ALL=(ALL) ALL     But that's all tangential; my actual question is: Why is this group called wheel? I've heard miscellaneous explanations for it before, but don't know if any of them are correct. Does anyone know the actual history of the term?