Is there a way to run servlet Filter only once?
Using special auto start servlet to initialize on startup and share application data
How would I prove that for all elements of a set {n | n ∈ ℕ ∧ n &gt; 7} (all natural numbers greater than 7), there are multiples of 3 and 5 which, when added up, are equal to that element of the set?  A := {n | n ∈ ℕ ∧ n &gt; 7} ∀ n ∈ A: n = x*3 + y*5   I do understand why this is true:   8 = 1*3 + 1*5 9 = 3*3 + 0*5 ...  15 = 0*3 + 3*5   and this pattern repeats once 16 is reached, as 8 can be replaced with 1*3 + 1*5, so I'd basically have to add 1 to x and y for every time 8 fits in n.  I am however not sure how I can formulate this mathematically correct.  Thanks in advance, CrushedPixel I found Sean Carroll's "A No Nonsense Introduction to General Relativity" (about page .  pdf ), a 24-page overview of the topic, very helpful for beginning study.  It all got me over the hump of learning the meaning of various terms associated with GR, most of which I had heard before without understanding.  It also outlined the most important examples.  Is there a similar document for quantum field theory, which presents the main equations, briefly describes the main ideas, and summarizes the most important applications and results so that the reader can feel the lay of the land before studying in depth? Line breaking with hyperref href with an underline in itemize I have a simple itemized list like the following MWE:  \documentclass[10pt,a4paper]{article} \usepackage[utf8]{inputenc} \usepackage{amsmath} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{graphicx} \usepackage{hyperref} \usepackage{lmodern} \usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry} \usepackage{lipsum} \begin{document} \begin{itemize} \item \href{http://google.com}{[ID1]: \underline{\lipsum[1]}} \end{itemize} \end{document}   This unfortunately doesn't break the block of text as expected, as shown below:    How can I fix this item so it will line break properly? I am trying to use the AwesomeCV template () for creating a CV using TexMaker 5.0.3 with XeLaTex. However, I am not able to get this to work as I get the following error messages:    Does anyone know what the source of problem might be and how to solve it?  Thanks a lot in advance,  Cheers Why don't we have an isomorphism between $R[x]$ and $ R[[x]]$? Flag pop-up hidden beneath answer box (and it's still transparent!) In an extract I am dealing with, I have 2 datetime columns. One column stores the dates and another the times as shown.  How can I query the table to combine these two fields into 1 column of type datetime?  Dates  2009-03-12 00:00:00.000 2009-03-26 00:00:00.000 2009-03-26 00:00:00.000   Times  1899-12-30 12:30:00.000 1899-12-30 10:00:00.000 1899-12-30 10:00:00.000 I have a JavaScript object like the following:  var p = {     "p1": "value1",     "p2": "value2",     "p3": "value3" };   Now I want to loop through all p elements (p1, p2, p3...) And get their keys and values. How can I do that?  I can modify the JavaScript object if necessary. My ultimate goal is to loop through some key value pairs and if possible I want to avoid using eval. The bug displayed in the attached screenshot occurs consistently for me while running the developer beta of iOS 10 using v1.5.2 of the Stack Exchange app on an iPhone 6.  I was able to recreate this by simply tapping on any question or answer in my feed with a long title. This doesn't appear to be a bug with iOS 10 itself since I haven't seen it in other apps, but I could be wrong. How to edit 'etc/hosts' file in non-rooted phone? I rent a VPS that uses a SSD of 10GB (Debian 7) and I upgraded yesterday to their "second tier" plan that uses a 20GB disk. However, the "one-click-upgrade" process didn't work as I expected and what they did was to move my data to a bigger drive without actually extending the partitions. So now I have 10GB of unallocated space.  I do run around 5 websites on this VPS with mail accounts and all that jazz and I'm very scared to mess up anything so I called their support and they offered to do the job for me for 80 EUR that I find unacceptable since I thought it was included when doing the upgrade. Their older offers from last year used to be just a one click job but the excuse is that "SSD's are different, so it's up to the user".  Anyway, how can I actually do that without screwing things up and is it possible to do that on a "live" system?  I know a couple of commands so here it goes what I could find:  root@vpsxxxxxx:~# df -h Filesystem      Size  Used Avail Use% Mounted on rootfs          9.9G  7.6G  1.8G  81% / udev             10M     0   10M   0% /dev tmpfs           388M  200K  388M   1% /run /dev/vda1       9.9G  7.6G  1.8G  81% / tmpfs           5.0M     0  5.0M   0% /run/lock tmpfs           775M     0  775M   0% /run/shm /dev/vda1       9.9G  7.6G  1.8G  81% /var/www/clients/client2/web2/log /dev/vda1       9.9G  7.6G  1.8G  81% /var/www/clients/client1/web3/log /dev/vda1       9.9G  7.6G  1.8G  81% /var/www/clients/client3/web5/log /dev/vda1       9.9G  7.6G  1.8G  81% /var/www/clients/client5/web7/log /dev/vda1       9.9G  7.6G  1.8G  81% /var/www/clients/client4/web6/log  root@vpsxxxxxx:~# fdisk -l  Disk /dev/vda: 21.5 GB, 21474836480 bytes 4 heads, 32 sectors/track, 327680 cylinders, total 41943040 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000     Device Boot      Start         End      Blocks   Id  System /dev/vda1   *        2048    41943039    20970496   83  Linux  root@vpsxxxxxx:~# sfdisk -l  Disk /dev/vda: 41610 cylinders, 16 heads, 63 sectors/track Warning: The partition table looks like it was made   for C/H/S=*/4/32 (instead of 41610/16/63). For this listing I'll assume that geometry. Units = cylinders of 65536 bytes, blocks of 1024 bytes, counting from 0     Device Boot Start     End   #cyls    #blocks   Id  System /dev/vda1   *     16  327679  327664   20970496   83  Linux /dev/vda2          0       -       0          0    0  Empty /dev/vda3          0       -       0          0    0  Empty /dev/vda4          0       -       0          0    0  Empty Windows update doesn't progress beyond 0 KB 0% I have Windows&nbsp;7 64-bit and the  isn't working properly. What can I do? When is the past perfect exactly needed? Setting Objects to Null/Nothing after use in .NET Should you set all the objects to null (Nothing in VB.NET) once you have finished with them?   I understand that in .NET it is essential to dispose of any instances of objects that implement the IDisposable interface to release some resources although the object can still be something after it is disposed (hence the isDisposed property in forms), so I assume it can still reside in memory or at least in part?  I also know that when an object goes out of scope it is then marked for collection ready for the next pass of the garbage collector (although this may take time).  So with this in mind will setting it to null speed up the system releasing the memory as it does not have to work out that it is no longer in scope and are they any bad side effects?  MSDN articles never do this in examples and currently I do this as I cannot  see the harm. However I have come across a mixture of opinions so any comments are useful. Words to describe people with good/poor vocabularies Words to describe people with good/poor vocabularies. I am looking for words which I can use to describe characters and I would also like to describe their vocabularies, and explain how their vocabularies stem from their upbringing Question: Suppose that $R$ is a commutative ring without zero-divisors.   Show that the characteristic of $R$ is either $0$ or prime.   I have established that every element in a commutative ring $R$ without zero divisors have the same additive order $n$.   Now, if no such additive order n exists, then the characteristic of $R$ is $0$.  Obviously, if a finite additive order exists, Char of $R$ is finite.  How do I show that Char of $R$ is prime? It probably involves lagrange's theorem and the order of the element in $R$.  Hint is appreciated.  Thanks in advance. What is the current state of apple device (iPhone, iPod, etc.) support? What ubuntu applications provide support? (guides, how to's, status) Also, specifically, details on support for syncing music to iPhone's and iPod's with the latest OS version:   Can you sync music to apple devices using >iOS4? (iPhone &amp; iPod) What applications allow you to do this and how? (guides, how to's, status)    What has already been established is:   Apple does not support Linux and has no plans to.  provides some support, however it currently does not support music/video synchronization with devices &gt;iOS4. Go to  and scroll to the section titled "" to see if your device version is supported. If $I$ and $J$ are ideals in a ring $R$ with $1$ such that $I+J = R$, show that $I^m$ and $J^n$ are co-maximal for all $m,n \in \mathbb{N}$ If $I$ and $J$ are ideals in a ring $R$ with 1 which are  co-maximal, i.e $I+J = R$, show that $I^m$ and $J^n$ are co-maximal for all $m,n$ in $\mathbb{N}$  Work done:     Should I proceed using    By taking $$K=I^m+J^m \neq R$$  Let $$S=\{I,J \in R \mid I^m+J^n \neq R \}$$ be the required partially order set ordered by inclusion then  $$I+J \subseteq I^n+J \subseteq I^n+J^m \subseteq \ldots $$  Then, I think this chain doesn't have an upper bound...as $I^m+J^n \neq R$ for all $ m,n \in \mathbb N$. Am I right??  Thanks for any help!! The ring $\Bbb Z\left [\frac{-1+\sqrt{-19}}{2}\right ]$ is not a Euclidean domain Find count of all combination of numbers whose sum is x