How to handel JsonMappingException try catch
Unable to catch JsonMappingException
Prove that for any piecewise smooth curve it is possible to find the parametrisation $\phi$ that is consistent with its length, ie.  length of a curve segment between $\phi(a)$ and $\phi(b)$ is equal to $|b-a|$.  It seems intuitive, but I don't have any idea how can I show this in the formal way. Integral $\int\!\sqrt{\cot x}\,dx $ Derivative of $x^{x^{\cdot^{\cdot}}}$? Per   I did the following:  ec2run ami-3c994355 --region us-east-1 -n 1 -t m1.large -z us-east-1d   On the machine:  sudo apt-get update sudo apt-get -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" dist-upgrade   I still get a prompt asking me which config file I want to use. These are the lines that come before the prompt:  Setting up grub-pc (1.99-21ubuntu3.1) ...   then:                           ┌───────────────────────────────────────────────────────┤ Configuring grub-pc ├───────────────────────────────────────────────────────┐                                                        │ A new version of configuration file /etc/default/grub is available, but the version installed currently has been locally modified.  │                                                        │                                                                                                                                     │                                                        │ What do you want to do about modified configuration file grub?                                                                      │                                                        │                                                                                                                                     │                                                        │                                     install the package maintainer's version                                                        │ Is the function $\mbox{tr}(XAX')$ convex? How to strike through obliquely, e.g. to indicate cancellation? How can I strike through an expression (e.g. "2x") obliquely, e.g. from bottom left to top right, so as to indicate cancellation? With the \sout command from the ulem package, I can only strike horizontally. trim is not part of the standard c/c++ library? Is it me or are there no standard trim functions in the c or c++ library? is there any single function that acts as a trim? If not can anyone tell me Why trim is not part of the standard library? (i know trim is in boost)  My trim code is  std::string trim(const std::string &amp;str) {     size_t s = str.find_first_not_of(" \n\r\t");     size_t e = str.find_last_not_of (" \n\r\t");      if(( string::npos == s) || ( string::npos == e))         return "";     else         return str.substr(s, e-s+1); }   test: cout &lt;&lt; trim("  \n\r\r\n \r\n text here\nwith return   \n\r\r\n \r\n "); -edit- i mostly wanted to know why it wasnt in the standard library, BobbyShaftoe answer is great. Can we set privacy for "last seen" status? Given $a,b,c,d \in \mathbb{Z}$, there is $x,y$ such that  $$(a^2 + b^2)(c^2 + d^2) = x^2 + y^2$$  One can show this by considering the complex number $a + bi$ and $c+ di$, using complex properties to deduce that $x = ac - bd, y = ad + bc$ is a solution.   However, given that either $a^2, b^2$ are distinct or $c^2,d^2$ are distinct, then how can one can find nonzero solutions $x,y$?  Sorry, I am assuming $a,b,c,d$ are nonzero. (Before anyone jumps to the conclusion that this is the same question as , please read it through. Also I am looking for more comprehensive and detailed data than the poster in .)  Many years ago I used to use a tool called Line Speed Meter (or Monitor) by TCPIQ. This was a brilliant piece of software that would sit quietly in the background and several times a day (according to a selectable frequency) would reach out and test internet line performance against servers all over the world. In the course of a week (or more), thousands of servers would be tested and enough data would accumulate that one could analyze performance according to time of day, day of week, location of server, etc. Drill-down was possible to the point where you could see every server that was tested.  This data was invaluable in determining if one really was getting the performance being paid for. It was also infinitely more valuable than spot checks you perform at sites like  or even the better-regarded ones like  or  (both of which, incidentally, are biased toward USA users - which I am not one of anymore).  Unfortunately Line Speed Meter is no longer supported and the company that made it now has instead a tool called isposure that is nowhere near as flexible or transparent - it is geared to supplying data to ISPs rather than to the consumers. For example, according to their FAQ, it usually runs only once a day automatically - I'd like to start with running it every couple of hours for a week or two - and scale back once I have a good basis so that I can notice when performance changes. Also, the details of the tests are no longer visible to the consumer-user.  My question: is there a (preferably free) tool/service available today to automatically collect comprehensive line speed metrics so I can map out and analyze the performance I am getting on my Broadband internet connection?  EDIT 2012-02-13: I left something out of the above.  In my country, each ISP sells a package that implies performance beyond the borders of my small country. They own (or lease) the lines going across the ocean. They have full control of the bandwidth leading from their servers to the backbones in the USA and EU. Peformance through the cloud is very much relevant and although not entirely, certainly largely under the local ISP's control, since traditionally, the bottleneck has been traffic out of the country.  As an example, at the moment, my ISP is advertising widely their new transatlantic cable and how their performance now outstrips everyone else's. I haven't "felt" it - so I want a tool to quantify it.  Performance within my country is usually good. The problem is that almost all my work involves access to the Internet in North America, Europe, Pacific Rim and others. So I care about and want to document the end-to-end performance I am getting from my ISP - and if I switch, compare to what I get at a new ISP.  EDIT 2013-03-07: As @harrymc pointed out I neglected to mention OS. All the machines on my home LAN are (sadly) Windows (XP or 7). If A tool requires *nix, I have a couple ancient machines in storage I could probably re-purpose - but my preference is for a Windows-based tool. Thanks.  EDIT 2013-03-10: As a further clarification - a method to monitor speeds achieved during regular work provides half of what I'm looking for. What was nice about TCPIQ is that it would ferret out thousands of sites around the world and do brief d/l &amp; u/l tests against them to check speed and then log the results. This gave a valuable statistical database for analysis of speed overall, as well as during times of day, days of week and according to geographical targets. That's the sort of functionality I'd like to achieve (again). For which values does the Matrix system have a unique solution, infinitely many solutions and no solution? Given the system:  $$\begin{align}  &amp; x+3y-3z=4 \\   &amp; y+2z=a \\  &amp; 2x+5y+(a^2-9)z=9 \end{align}$$  For which values of a (if any) does the system have a unique solution, infinitely many solutions, and no solution?    So I am getting that it has: infinitely many solutions at: (-1)    No solution at (1)    Unique solution at (-1,1)    AM I RIGHT?? List of all "partitions"/ "cuttings" of a list How to call shell commands from Ruby How do I call shell commands from inside of a Ruby program? How do I then get output from these commands back into Ruby? Default currency symbol I have a High poly mesh and I have decided to make the low poly by merging as it is easiest for me. Would it be possible to change the W Hotkey , so that it merges to the center automatically? It is time consuming pressing W > Merge > Center. Error in Obj-C : Expected identifier or '(' Do we still need swap partitions on desktops? I have read , but it was asked in the context of servers not desktops or notebooks.  If a good amount of RAM is installed on a notebook, say 8 GB, do we still need a swap space? Plotting solutions to NDSolve How do I install Adobe Flash player? I have had significant problems with watching flash video in 64-bit Ubuntu.  Does anyone know of a good way to get flash running on the platform? I'm looking to create a simple short-lived reservation system, and I'd like to generate confirmation numbers that are   unique random-looking alphanumeric short-ish, at least much shorter than 32 character-long strings returned by sha1   I'm only looking to have ~500 reservations, so I don't imagine high likelyhood of collissions.  One idea I had is generate an sha1 hash based on a date-time stamp and username, then truncating it to its first 10 characters.  Would something like that be reliably unique enough for the purposes of processing ~500 reservations?