JSP to hashmap?
Can a Spring form command be a Map?
PHP in_array() / array_search() odd behaviour SPSite.Exists returning true for a just deleted site collection Short story - I have a process that creates some sitecollection, so to test it I keep deleting and recreating the same site over and over. The process includes a check with the istruction SPSite.Exits, done to check if the sitecollection is present or should be created.  Sometime, soon after I delete the site collection, SPSite.Exists will report it as still available. Is this a cache related problem? What is the reasoning behind the design decision to allow users to create a display name which matches another existing users exactly?    This is opposed to the common practice of enforcing unique user names, and I'd really like to learn something. Can we use "there is" for plural nouns? "User accounts" or "users account" The question at hand is:  "Two capacitors of capacitances $C_1$ and $C_1$ have charge $Q_1$ and $Q_2$. How much energy, $\Delta w$, is dissipated when they are connected in parallel. Show explicitly that $\Delta w$ is non-negative."  I'm confused about what the physical situation is. I took the assumption that these capacitors were somehow pre-charged, and then connected to each other in parallel without a voltage source. However, I don't understand how this would work. If a circuit is composed of only 2 elements, I don't see how they could be in any arrangement but series. Nevertheless, I tried solving it that way:  Two capacitors in parallel have the same voltage drop. Charge will be redistributed to make it the same voltage for both. Let $Q_1'$ and $Q_2'$ be the charges on the capacitors after they are connected. Now, picture the equivalent capacitor  $C_{eq} = C_1 + C_2 =$ $\frac{Q_1' + Q_2'}{V_f}$   conservation of charge:  $Q_1' + Q_2'= Q_1 + Q_2$,        $C_{eq} =$ $\frac{Q_1 + Q_2}{V_f}$  $V_f = $$\frac{Q_1 + Q_2}{C_1 + C_2}$  The initial energy of the capactiors is:  $U_0 = $$\frac{Q_1^2}{2C_1}$$+\frac{Q_2^2}{2C_2}$  $U_f = $$\frac{1}{2}$$(C_1 + C_2)V_f^2 = $$\frac{(Q_1 + Q_2)^2}{2(C_1 + C_2)}$  $\Delta U$$ = $$\frac{(Q_1 + Q_2)^2}{2(C_1 + C_2)}$-$\frac{Q_1^2}{2C_1}$$-\frac{Q_2^2}{2C_2}$  However, I don't see how this is necessarily non-negative. Simplify $\prod_{k=1}^5\tan\frac{k\pi}{11}$ and $\sum_{k=1}^5\tan^2\frac{k\pi}{11}$ My question is:  If $\tan\frac{\pi}{11}\cdot \tan\frac{2\pi}{11}\cdot \tan\frac{3\pi}{11}\cdot \tan\frac{4\pi}{11}\cdot \tan\frac{5\pi}{11} = X$ and $\tan^2\frac{\pi}{11}+\tan^2\frac{2\pi}{11}+\tan^2\frac{3\pi}{11}+\tan^2\frac{4\pi}{11}+\tan^2\frac{5\pi}{11}=Y$ then find $5X^2-Y$.  I couldn't find any way to simplify it. Please help. Thanks. Toolbar options are not displaying in Edit Profile - About me section How do I create a file and mount it as a filesystem? How do I create a file of size 10M, format it with ext3 filesystem and then mount it in /media/fuse?  I tried with  mkfs -t ext3 file   then to mount it  mount -t ext3 file /media/fuse   It didn't work because it said that file wasn't a block device. Can anybody help me? How do I make a program auto-start every time I log in? I frequently need to start several programs that I use every time I start my computer. How can I make it so that whenever I login the program is automatically launched? I'm trying to write an automated test of an application that basically translates a custom message format into an XML message and sends it out the other end.  I've got a good set of input/output message pairs so all I need to do is send the input messages in and listen for the XML message to come out the other end.  When it comes time to compare the actual output to the expected output I'm running into some problems.  My first thought was just to do string comparisons on the expected and actual messages.  This doens't work very well because the example data we have isn't always formatted consistently and there are often times different aliases used for the XML namespace (and sometimes namespaces aren't used at all.)  I know I can parse both strings and then walk through each element and compare them myself and this wouldn't be too difficult to do, but I get the feeling there's a better way or a library I could leverage.   So, boiled down, the question is:  Given two Java Strings which both contain valid XML how would you go about determining if they are semantically equivalent?  Bonus points if you have a way to determine what the differences are. Cannot move file to trash warning when trying to delete a file in Nautilus I am trying to delete files in Nautilus and every time I try to delete one it always gives me this message:     Cannot move file to trash, do you want to delete immediately?   Then it gives me several questions. All I want is that when I press Delete in the keyboard, it sends it automatically to the trash can. Not to ask me every time.  The problem relates to NTFS partitions, external drives but also include Linux filesystems.  What are the reasons for nautilus beeing not able to move to trash? What is the possessive of "you guys"? How to remove configuration files completely Recently I uninstalled some software using sudo apt-get --purge autoremove, thinking that this would remove all traces of it including unused dependencies and configuration files. However I discovered that a configuration file was left behind in my home folder.  Is there a more powerful command which would remove even that?   Also, is it safe to delete the hidden files and folders under home, if they are merely configuration files, or are there other kinds of files? Why does it says "welcome back -user- click here to 'refresh page'" After logging into one Stack Exchange site, when I visit another SE site, it says to me, welcome back - user - click here to refresh - web page.   Isn't it possible to refresh the page using code &amp; without the user's interaction? Profile tab hyperlink should match name change Run a command without making me wait On the CLI, sometimes a command I type takes a while to complete, and sometimes I know when that's about to happen. I'm a bit confused on "backgrounding" and such in Linux.  What is the most common (or user-friendly way) of telling the CLI that I don't want to wait, please give me back my prompt immediately. And if it could give me a progress bar or just busy-spinner, that would be great! What happens to net acceleration in a non-inertial reference frame with cenripetal force? In a non-inertial reference frame, the centripetal force is balanced by a centrifugal force. Therefore, shouldn't the net acceleration be zero? Yet, you still feel an acceleration outwards? Why is that? Why is Ubuntu using so much memory? I have just turned on my PC and have two applications running; Thunderbird and Firefox. Whatever else is running is part of Ubuntu's feature set (as well as a few indicators).  This has been ongoing for weeks, so I'm not sure if it's normal behaviour or not.  Right now, my memory usage indicator says that Ubuntu is using 41% of my 6GB of RAM. I haven't even opened Gimp or my other day-to-day things. I'll be buying another 6GB of RAM, this week, so that I don't run out when using Gimp or Openshot, for example.  An overview of my running applications shows that Nautilus is using the most, yet it isn't even open. This seems a little excessive, or am I missing something? Least rank of a matrix Let $A$ be a $7\times 7$ matrix such that it has rank $3$ and $a$ be $7\times 1$ column vector.  Then least possible rank of $A+(a a^T)$ is? ($a^T$ is transpose of the vector)  Intuitively I think it's $2$ as $a a^T$ has rank $1$, and the most it could affect is one row of $A$.