java.lang.NullPointerException: Attempt to invoke virtual method 'boolean com.refresh.pos.domain.sale.kas.addKas1(java.lang.String, double)'
What is a NullPointerException, and how do I fix it?
How to access specific raw data on disk from java Do we need inertial frames in Lagrangian mechanics? Inverse of Heine–Cantor theorem Geometry with Trigonometry From the given figure, prove that      $$\cot\ \theta=\cot\ A+\cot\ B+\cot\ C$$     I could not even start to the first point. Please help me to solve this.  Thanks in advance I'm writing an essay, and want to know the promotion rate and average duration from assistant professor to associate professor and associate professor to professor in recent years. Sadly I don't know the data for the US. Could anyone tell me? Disable password request from suspend - 18.04 Who owns R2-D2 & C-3PO in the Prequel trilogy? Is there any concrete evidence that Anakin officially owned R2-D2 or C-3PO?  I found this episode of Star Wars: Clone Wars that shows it, but it's fairly vague... HTML text input allow only numeric input Is there a quick way to set an HTML text input (&lt;input type=text /&gt;) to only allow numeric keystrokes (plus '.')? How to show that when the linear transformation $\Phi =\psi \circ \phi : E \rightarrow G$ is injective, then $\phi$ is also injective? How to show that when the linear transformation $\Phi =\psi \circ \phi : E \rightarrow G$  (where $\phi : E \rightarrow F$ and $\psi : F \rightarrow G$) is (1) injective, then $\phi$ is injective and when (2) $\Phi$ is surjective, then $\psi$ is also surjective ?  I've tried to prove it by the definition of injection and surjection, but I'm not convinced myself by it.  For example, in the first case :  If $\Phi$ is injective, $\forall g \in G$, we have $0$ or $1$ $e \in E$ such as $\Phi(e)=g$.  $\Rightarrow \Phi(e) = \psi(\phi(e)) = \psi(f) =g$.   So $\forall f \in F$, we also have $0$ or $1$ $e \in E$ such as $\phi(e)=f \in F$.   $\Rightarrow \phi$ is injective.  Is this right or did I prove nothing at all ? I think it is easier to convince myself/ to understand with surjectivity but still.. How many times can American Tourist re-enter UK in same 6 month period? How do I put big brackets under different parts of an equation so that I can write, e.g., text specific to these parts? For example: f =  x^3 +  2     |___|  |__|        |     |    text 1  text 2 Why are the shebang parts of the following elementary scripts not working:  $ cat hello.sh #! /bin/sh echo Hello $ ./hello.sh bash: ./hello.sh: /bin/sh^M: bad interpreter: No such file or directory  $ cat hello.py #! /usr/bin/env python3 print("Hello") $ ./hello.py : No such file or directory   whereas calling the interpreter manually is working:  $ sh hello.sh Hello $ python3 hello.py Hello Placing a single algorithm in two columns How do I get an XBOX 360 controller working? I have a Microsoft XBOX 360 gamepad with the wireless adapter and I was wondering what I would have to install to use them with Ubuntu I do know that when using this on Windows I have to manually install the drivers for the wireless receiver (if that is relevant.) How can I run everything as root I have dual booted to lubuntu (with Windows XP) and everytime and then I'm getting asked for my password. How do I run everything as root and not ask a password again? Ideally I wanted to run nginx but it has permission denied issues:  apathetic@ubuntu:~$ service nginx start Starting nginx: nginx: [alert] could not open error log file: open() "/var/log/nginx/error.log" failed (13: Permission denied) 2012/08/03 20:06:25 [warn] 4762#0: the "user" directive makes sense only if the master process runs with super-user privileges, ignored in /etc/nginx/nginx.conf:1 nginx: the configuration file /etc/nginx/nginx.conf syntax is ok 2012/08/03 20:06:25 [emerg] 4762#0: open() "/var/run/nginx.pid" failed (13: Permission denied) nginx: configuration file /etc/nginx/nginx.conf test failed Why am I getting strange results when using a power meter to measure CFLs? CPU governor changes automatically to "performance" under load I have a Lenovo T570 with Xubuntu 18.04 LTS. My current issue is that my cpu speed stepping is kind of going nuts and does what ever it thinks its best.  Sample: when I run my IDE and cpu load increases during build time, the governor changes automatically. I caught the moment during compiling my project with the following call:  martin@martin-ThinkPad-T570:~$ while cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor; do sleep 1; done powersave powersave performance performance   cpufreq-info tells me this:  martin@martin-ThinkPad-T570:~$ cpufreq-info  cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 Report errors and bugs to cpufreq@vger.kernel.org, please. analyzing CPU 0:   driver: intel_pstate   CPUs which run at the same hardware frequency: 0   CPUs which need to have their frequency coordinated by software: 0   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.25 GHz. analyzing CPU 1:   driver: intel_pstate   CPUs which run at the same hardware frequency: 1   CPUs which need to have their frequency coordinated by software: 1   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz. analyzing CPU 2:   driver: intel_pstate   CPUs which run at the same hardware frequency: 2   CPUs which need to have their frequency coordinated by software: 2   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.26 GHz. analyzing CPU 3:   driver: intel_pstate   CPUs which run at the same hardware frequency: 3   CPUs which need to have their frequency coordinated by software: 3   maximum transition latency: 4294.55 ms.   hardware limits: 400 MHz - 3.50 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 3.50 GHz and 3.50 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.36 GHz.   Please take a look at     current policy: frequency should be within 3.50 GHz and 3.50 GHz.       The governor "performance" may decide which speed to use   Afterwards to go back to powersave I use my little script:  martin@martin-ThinkPad-T570:~$ cat cpu_freq_save.sh  #!/bin/bash sudo cpufreq-set -g powersave -c 0 --min 400MHz sudo cpufreq-set -g powersave -c 1 --min 400MHz sudo cpufreq-set -g powersave -c 2 --min 400MHz sudo cpufreq-set -g powersave -c 3 --min 400MHz   Which resets the min frequency and the governor but as soon as I compile again with my IDE every time the governor and the min frequency changes again.  Any idea how I can disable that automatic change?  PS: If you need more details, just tell me where to find them and I will provide them How to calculate stays against 90/180 visa rules? Some destinations have a "90/180 rule" which says you can come and go but you must not spend over 90 days out of any 180 days in the area.  concerns this rule.  At least Schengen and Turkey have this rule, probably depending on where the traveller is from and what kind of visa they apply for.  Maybe I'm a dummy but I've always had a lot of trouble trying to add up how many days I've spent in such places when I've entered and left several times over recent months.  Is there an easy way to do this I'm missing or is it difficult for everybody? I'm guessing something based on counting backwards from the end date might be the trick?  Maybe you know of an app or website that can do this for you. "Do you want to continue[Y/n]?" Why the upper case? I am new to Ubuntu and some little thing start to bug me. Such as when trying to install a program, Ubuntu asks,     Do you want to continue[Y/n]?   What is bugging me is why the letter "Y" is upper case and "n" is lower case. Do they have any significant reason why one is upper and the latter is lower? Whatever case I enter it doesn't change the outcome: it either continues or not. Are they trying to notify us that we can enter both and it won't change anything? In C# check that filename is *possibly* valid (not that it exists) Is there a method in the System.IO namespace that checks the validity of a filename?  For example, C:\foo\bar would validate and :"~-* would not  Or a little trickier, X:\foo\bar would validate is there is an X: drive on the system, but wouldn't otherwise.  I suppose I could write such a method myself, but I'm more interested in a built-in one.