Why does an object throw nullPointerException on RestoreInstanceState?
What is a NullPointerException, and how do I fix it?
Backup with duplicity on Google Cloud Storage I have already set a backup routine that backups all my files to Amazon S3 using duplicity. I would like to create a similar backup routine with Google Cloud Storage. Is it possible to get duplicity to work with GCS? MySQL Seems to be crashing quite often, I'd say every hour or so.   The only thing running on this server that is using MySQL is a Drupal installation that I'm working on, there's only one person that's using it and it literally has around three pages - from what I can gather this seems to be a memory issue with innoDB? I'm not great at this stuff so I'm unsure.  Any guidance? Here's the relevant parts from my error.log  140216 14:20:01 [Note] Plugin 'FEDERATED' is disabled. 140216 14:20:01 InnoDB: The InnoDB memory heap is disabled 140216 14:20:01 InnoDB: Mutexes and rw_locks use GCC atomic builtins 140216 14:20:01 InnoDB: Compressed tables use zlib 1.2.3.4 140216 14:20:01 InnoDB: Initializing buffer pool, size = 128.0M InnoDB: mmap(135987200 bytes) failed; errno 12 140216 14:20:01 InnoDB: Completed initialization of buffer pool 140216 14:20:01 InnoDB: Fatal error: cannot allocate memory for the buffer pool 140216 14:20:01 [ERROR] Plugin 'InnoDB' init function returned error. 140216 14:20:01 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 140216 14:20:01 [ERROR] Unknown/unsupported storage engine: InnoDB 140216 14:20:01 [ERROR] Aborting  140216 14:20:01 [Note] /usr/sbin/mysqld: Shutdown complete  140216 14:20:02 [Note] Plugin 'FEDERATED' is disabled. 140216 14:20:02 InnoDB: The InnoDB memory heap is disabled 140216 14:20:02 InnoDB: Mutexes and rw_locks use GCC atomic builtins 140216 14:20:02 InnoDB: Compressed tables use zlib 1.2.3.4 140216 14:20:02 InnoDB: Initializing buffer pool, size = 128.0M InnoDB: mmap(135987200 bytes) failed; errno 12 140216 14:20:02 InnoDB: Completed initialization of buffer pool 140216 14:20:02 InnoDB: Fatal error: cannot allocate memory for the buffer pool 140216 14:20:02 [ERROR] Plugin 'InnoDB' init function returned error. 140216 14:20:02 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 140216 14:20:02 [ERROR] Unknown/unsupported storage engine: InnoDB 140216 14:20:02 [ERROR] Aborting  140216 14:20:02 [Note] /usr/sbin/mysqld: Shutdown complete   EDIT The server is the lowest-spec DigitalOcean Droplet with 512MB RAM. This particular Droplet is running NodeJS, MySQL and Apache. There's a low-traffic static site, a Ghost blog and this Drupal site I'm developing.   Should I just upgrade the RAM, or is there something I can do to fix this? Skipping acquire of configured file 'contrib/binary-i386/Packages' as repository ... doesn't support architecture 'i386' I installed Ubuntu 18.04 and then while installing Virtualbox i get the 'i386' error message after I did:  $ sudo apt-get update Get:1 http://nl.archive.ubuntu.com/ubuntu bionic InRelease [242 kB] Hit:2 http://security.ubuntu.com/ubuntu bionic-security InRelease                                                                 Hit:3 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu bionic InRelease                                          Hit:4 http://nl.archive.ubuntu.com/ubuntu bionic-updates InRelease Hit:5 http://nl.archive.ubuntu.com/ubuntu bionic-backports InRelease Get:6 http://download.virtualbox.org/virtualbox/debian bionic InRelease [4429 B] Get:7 http://download.virtualbox.org/virtualbox/debian bionic/contrib amd64 Packages [1426 B] Fetched 248 kB in 1s (209 kB/s)      Reading package lists... Done N: Skipping acquire of configured file 'contrib/binary-i386/Packages' as repository 'http://download.virtualbox.org/virtualbox/debian bionic InRelease' doesn't support architecture 'i386'   I found several answers on Askubuntu for the 'i386' message but I don't know how to apply this to my situation How to take the gradient of the quadratic form? Close Vote Review Audits are too obvious The other day, I got an obviously good question in a Close Vote Review.  Even if I didn't read the question,  is a bit of a giveaway.  Today I got one where   Also, on sites other than SO (where I understand the queues are huge), the number of reviews needed is often low enough (single digits) that you usually notice when you get an extra one.  I don't mind - I'm quite happy to get easy-to-pass audits - but maybe they could be a little harder... Label PGFPlot table points with coordinates I would like to label each plotted point with its x and y coordinate. I am able to label with a single one using the MWE below. I must avoid manually labeling each point since my actual table size is larger and will be changed out regularly. \documentclass{standalone}   \usepackage{tikz} \usepackage{pgfplots} \pgfplotsset{compat=1.16}  \begin{document}  \pgfplotstableread[col sep=&amp;,row sep=\\]{  x     &amp;  y     \\  0.940 &amp;  0.992 \\  0.992 &amp; -0.940 \\ -0.992 &amp;  0.940 \\ -0.940 &amp; -0.992 \\ }\mytable  \begin{tikzpicture}  \begin{axis}     \addplot+[only marks, nodes near coords]table[x=x,y=y,meta=x]{\mytable}; \end{axis}  \end{tikzpicture} \end{document}  which creates the following figure  The desired output is for each point to be labelled with both coordinates. For specific example the top left point would be labelled with &quot;(0.94, 0.992)&quot;. Can a unit test project load the target application's app.config file? I am unit testing a .NET application (.exe) that uses an app.config file to load configuration properties.  The unit test application itself does not have an app.config file.    When I try to unit test a method that utilizes any of the configuration properties, they return null.  I'm assuming this is because the unit test application is not going to load in the target application's app.config.  Is there a way to override this or do I have to write a script to copy the contents of the target app.config to a local app.config?     post kind-of asks this question but the author is really looking at it from a different angle than I am.  EDIT: I should mention that I'm using VS08 Team System for my unit tests. I have a couple of illustrations done in Illustrator and I am planing to animate it for a website that I am working on, I've heard of  toolkit with flash, but is it the best way to go or is there another "better" way of doing it?  Here's an example of the kind of animations I am aiming for: Random errors on various sites when viewing main page Occasionally (very occasionally) when returning to the main page of a site by clicking on the logo I get the following message:     It was not possible to perform this tag search at this time due to an unexpected error.   This is odd because I'm not performing a tag search.  So far this has happened on both Movies &amp; TV and Cooking.  I have heard that others are getting this same message. Using R, I have fitted a linear model for a single response variable from a mix of continuous and discrete predictors. This is uber-basic, but I'm having trouble grasping how a coefficient for a discrete factor works.   Concept: Obviously, the coefficient of the continuous variable 'x' is applied in the form y = coefx(varx) + intercept but how does that work for a factor z if the factor is non-numeric? y = coefx(varx) + coefz(factorz???) + intercept   Specific: I have fitted a model in R as lm(log(c) ~ log(d) + h + a + f + h:a) where h and f are discrete, non-numeric factors. The coefficients are:  Coefficients:               Estimate  (Intercept)  -0.679695  log(d)        1.791294  h1            0.870735   h2           -0.447570   h3            0.542033    a             0.037362   f1           -0.588362   f2            0.816825  f3            0.534440 h1:a         -0.085658 h2:a         -0.034970  h3:a         -0.040637   How do I use these to create the predictive equation:  log(c) =  1.791294(log(d)) + 0.037362(a) + h??? + f???? + h:a???? + -0.679695   Or am I doing it wrong?   I THINK that that concept is if the subject falls in category h1 and f2, the equation becomes:   log(c) =  1.791294(log(d)) + 0.037362(a) +  0.870735  + 0.816825  + h:a???? + -0.679695   But I'm really not clear on how the h:a interactive term gets parsed. Thanks for going easy on me. In the calculus of variations, particularly Lagrangian mechanics, people often say we vary the position and the velocity independently. But velocity is the derivative of position, so how can you treat them as independent variables? I am a final year PhD in UK in a scientific discipline and I am writing my thesis. I have already published 2 journal papers and I have submitted 2 more papers for publications. My department does not allow a "publications-based" thesis so I need to write a thesis in the context of a book etc.   As I write my thesis in a couple of places, especially in the literature review, I tend to reuse sentences from my publications. I try to restate them a bit, maybe change some words for their synonyms etc. but it is practically me writing about what I wrote before. It goes without saying that I cite/quote me at the end of a passage if I say something non-obvious (I found that slightly funny. :) ). The problem is that occasionally I am just explaining for instance how a certain estimation technique works; in that case I cite the original authors and not myself. The syntax in those occasions though is practically the same as the original passage I used in my publication; as I have explained it once and was consider good, I find no reason to reinvent myself (I do a mild rewording as I mentioned but that is quite insignificant). Same things goes for listings. I do cite my paper in the beginning of a big list as the list's source but the list itself is almost identical as the one in "my" paper; in those cases I don't use quotations, just attribution "[]".  Is there an obvious guideline? The basic definition of plagiarism "reproducing the work of another person's as your own" is not (directly) applicable to me because I am the other person (almost *); if I am using other people's work I do cite them but I don't cite myself, citing them, in quotation marks!  I am a bit "fuzzy" about how not to plagiarize myself in my thesis (I have had no problem regarding my journal publications).  (* In all publications mentioned I am the first -but not sole- author.) How can I install Windows software or games? I am trying to solve the following exercise.      Assume that $m$ and $n$ are co-prime positive integers, and that $k$ is a field. Prove that the ideal generated by $x^{m} - {y^n}$ is a prime ideal in $k[x,y]$.   I tried the following approach : Consider the ring homomorphism ${\varphi}:k[x,y]\rightarrow{k[t]}$ defined by $\varphi(x) = t^n$, and $\varphi(y) = t^m$, and extend $\varphi$ to $k[x,y]$ to ensure that it is a ring homomorphism. Then the ideal $(x^m - y^n)$ is clearly contained in the kernel of $\varphi$. It remains to prove the reverse set inclusion. i.e. to prove that this ideal is exactly equal to the kernel of $\varphi$. I don't know how to go about this! Most efficient way of booking academic supervision appointments I'm wondering if there's a more efficient method of booking an academic supervision appointment. The method I experienced was a schedule on the professor's door, first-come-first-serve.   How do we employ technology that is the most efficient (reduces scheduling time, permitting all students to view sign ups)? Cocos2d-x supporting multi-resolution using density independent pixels Is there a way to use Density Independent pixels(dp) in cocos2d-x?  I am developing an Android game using Cocos2d-x 3.0.  The Android reference  tells me not to use pixels in code but use dp when supporting multi-resolution support. It also tells me to provide different images for different screen size groups and different density groups.  However, cocos2d-x tutorials use pixels for multi-resolution support. If I were to use pixels, I think it means I need to have images for all these different resolutions:  240x320, 240x400, 240x432 320x480 480x640, 480x800, 480x854 600x1024 640x960 1024x600, 1024x768 1280x768, 1280x800 1536x1152 1920x1152, 1920x1200 2048x1536 2560x1536, 2560x1600  Even if I don't support every screen resolutions, I think this requires more work than following the Android reference's best practice.  Am I missing something on how supporting multi-resolution works or do I indeed do need to do much more work using cocos2d-x? Is the set of partial order relations over $ \mathbb{N}$ countable? I think it's uncountable but don't know how to prove this. I would be very helpful if someone could also give some kind of a strategy for proving uncountability, in particular how to find injective or surjective functions that help proving this. The limit of truncated sums of harmonic series, $\lim\limits_{k\to\infty}\sum_{n=k+1}^{2k}{\frac{1}{n}}$ When you add an image strip to the Video Sequence Editor, it stretches/shrinks your image to fit the full output frame.  How can I add an image at its original resolution?  For example, if I add a 60x60 pixel image, it should appear very small in the final 1080p render. I am intermediate in PHP. To polish my skills I start learning Drupal 7. While learning Drupal architecture concepts, the terms hooks and bootstrapping puzzled me a lot. I read the "Pro Drupal development" book, and some documentation on drupal.org, but it is so advanced for me to learn how hooks work in Drupal to display the web page.  Can anyone tell me what hooks are in simple words?