NullPointerException on my amateur benchmark program
What is a NullPointerException, and how do I fix it?
So to help prevent brute force attacks against my phpmyadmin install I've configured nginx to require HTTP Basic Auth (extra username and password) and then the requests need to come from a whitelisted IP Address. However the IP Address whitelist works fine if I run  however without adding the extra .php block I could load  without my IP being whitelisted. This issue doesn't affect the HTTP Basic Auth. Is there a reason this happens? Anyway to get around having to add extra .php blocks? A copy of the config area for phpmyadmin is below.  # Setup and secure phpMyAdmin location /phpmyadmin/ {   allow 1.2.3.4;   deny all;   auth_basic "phpMyAdmin - HTTP Basic Login";       auth_basic_user_file /etc/nginx/pma_pass;     location ~ \.php$ {     include snippets/fastcgi-php.conf;             fastcgi_pass unix:/run/php/php7.0-fpm.sock;     allow 1.2.3.4;     deny all;     } } Just freeze an application (suspend the CPU, save its state to disk) and 'defrost' it when I want to use it 4 weeks later. Programmatically selecting non adjacent Cells Conjectures Involving floor(x)/piecewise continuity with regards to Integration and Differential Equations [This answer has been heavily edited in response to a long chain of comments on Eric Stucky's answer.]  I came up with these few theorems and I am curious whether or not my hypothesis are true. I don't really have a method for proving these, mind you. I'm more considering these as things I've noticed to be true. I just don't know whether they are always true.  Some of these are definitions to which I will append "def." to the end of the title. Think of these as a given. It's like how the integral is defined abstractly as area. I'm defining terms.  Jump Series Theorem def.  A function $f$ [consisting of floor] is said to have a jump series if there is a series $\Sigma=\sum_{n=1}^\infty a_nH_n$ of scaled step functions such that $f+\Sigma$ no longer has any discontinuity attributable to floor. The sequence of scaling factors $a_n$ is called the jump sequence for the function.  Definition of Implied Derivative def.  We define the evaluation of the implied derivative of a function $y$ at the point $x$ as the set of values $y^{\to}(x) = \{y | y = \lim_{h \to 0^+} \frac {y(x+h) - f(h)}{h} \lor y = \lim_{h \to 0^-} \frac {y(x+h) - f(h)}{h}\}$. It is in this sense that the implied derivative has the potential of being a multi-valued operator.  Jump Series Resolution Theorem  [The original wording is preserved; I have a formalism but it assumes that having a jump function is equivalent to being piecewise continuous, which I'm not sure is true.]   The integral of a floor-based function is floor treated as a constant minus the appropriate jump series of the integral.  Integration Continuity Theorem  The (ordinary) indefinite integral of any function $f$ having a jump series must be continuous (or fixably discontinuous) on the domain of $f$. However, this can vary for the implied indefinite integral.  Calculus Jump Theorem def.  [Again, the original wording is preserved; the meaning of this phrase has not been properly illuminated]  Any form of jumping within a function representable as a floor function can be considered as a portion of the constant of the implied integration for floor.  Jump Location Theorem  For any function $a(x)$ with a jump series, the function $\lfloor a(x)\rfloor$, has points of discontinuity precisely at those $x$ such that $a(x) - [a(x)] = 0$.  Composite Floor Function Jump Sequence Theorem One  If $a$ is a function such that $a(x) - \lfloor a(x) \rfloor = 0$ when $x - \lfloor x \rfloor = 0$, then the jump sequence of the composite function $f(x - \lfloor a\rfloor)$ is a constant value $f(0) - f(1)$.  Implied Differential Equations Conjecture  Any continuous solution to an equation constructed with implied derivatives of various orders is the same as the solution to the similarly constructed differential equation. How to open a folder in Finder by a single mouse click? (using Icon view) Is there a setting, key combination or similar to open a folder/subfolder in Finder with a single mouse click ?  I need a general solution which works on any folder in effort to minimize needless clicking ... that tiny triangle aside the folder icon will work yet its just too small and only appears using list view ... inspired by same behavior on osx inside a browser to hold down command key and single click a web link ... forcing users to double click is so 20th Century  Is there a way to enable this on macOS (High Sierra or higher)?  On ubuntu this single click preference is a simple setting ;-) What are alternatives to ExtJS? So what I'm looking for is a javascript framework I can use that has several UI controls. I have taken a look at  but those controls are very basic compared to ExtJS. Are there any other competitive alternatives?     This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. More info: . How do I remove old kernel versions to clean up the boot menu? Every time I install a new Linux kernel, it gets left in the grub_config, making the boot menu longer each time.    I know I can manually search through the installed packages and remove them.  Does Ubuntu provide any easier way to clean them up or keep them from showing in the boot list? I was given a laptop with a totally dead display. I do not want to pay to replace the broken display, but I would like to use the laptop as a server and connect to it via SSH to control it.  I have pulled out the internal hard drive from the broken laptop, and I want to install Debian GNU/Linux and the SSH server onto this HDD using a working Debian laptop.  However, the hardware in the two laptops is very different, and I am wondering what kind of problems I would run into when I plugged the drive back in to the laptop with the broken display because of this?  How would I make this work? What is the proper way for me to install a bootable copy of Linux onto a HDD that will be used by a computer with different hardware? Why are there not generic phone OS installers? Is there a word that describes a parent whose child has died?   Along the lines of "orphan", "widow", and "widower", is there a single word for a parent who has lost a child (of any age)? I am a US citizen and have recently visted the UK  with simply a passport which allowed me to vist for 6months I have heard rumors that I am obligated to stay in the US for a Equal amount of time that I have visited the UK before I am able to return, but I am struggling tour no any proof of this obligation .. Am I missing somthing or is it simply not true Convince grep to output all lines, not just those with matches Say I have the following file:  $ cat test  test line 1 test line 2 line without the search word another line without it test line 3 with two test words test line 4   By default, grep returns each line that contains the search term:  $ grep test test  test line 1 test line 2 test line 3 with two test words test line 4   Passing the --color parameter to grep will make it highlight the portion of the line that matches the search expression, but it still only returns lines that contain the expression. Is there a way to get grep to output every line in the source file, but highlight the matches?  My current terrible hack to accomplish this (at least on files that don't have 10000+ consecutive lines with no matches) is:  $ grep -B 9999 -A 9999 test test     If grep can't accomplish this, is there another command-line tool that offers the same functionality? I've fiddled with , but it doesn't seem to have an option for it either. How to run a specific program as root without a password prompt? I need to run something as sudo without a password, so I used visudo and added this to my sudoers file:  MYUSERNAME ALL = NOPASSWD: /path/to/my/program   Then I tried it out:  $ sudo /path/to/my/program [sudo] password for MYUSERNAME:    Why does it ask for a password? How can I run/use commands as root with a non-root user, without asking for a password? Prove that $\mathbb Z_{m}\times\mathbb Z_{n} \cong \mathbb Z_{mn}$ implies $\gcd(m,n)=1$. Prove that $\mathbb Z_{m}\times\mathbb Z_{n} \cong \mathbb Z_{mn}$ implies $\gcd(m,n)=1$.  This is the converse of the Chinese remainder theorem in abstract algebra. Any help would be appreciated.  Thanks! How to change the shadow color in Blender Cycles? I want to change the color of the shadow casting by a cube to green. While it's very easy to do it in Blender Internal (you select the lamp, go to the Lamp data header and change the shadow's color in the Shadow panel) in Cycles there're no such options. How to achieve it in Cycles? Error when using TikZ-Feynman package How to securely delete files stored on a SSD? I understand using phone while it is being charged by a normal charger is not advised. What about using phone while it is being charged by a portable charger (powerbank)?  I own a HTC one and i was told by a mobile technician HTC’s own portable charger only should be used for HTC one. How much truth is there to it as HTC powerbank is not available in my city and i am thinking of using Sony portable charger for charging my HTC One? I masked an image in the UV/Image editor masking section. I then used that mask in the compositor for background replacement. However, the mask size seems to be different. Why is that? Here's a screenshot: How can you prove that the normal equations: $(X^TX)\beta = X^TY$ have one or more solutions without the assumption that X is invertible?  My only guess is that it has something to do with generalized inverse, but I am totally lost.