Jsoup null pointer exception
What is a NullPointerException, and how do I fix it?
Can polymorphing monsters spam their ability to effectively give themselves a massive health pool? Some creatures have an ability that lets them polymorph, such as the Couatl's Change Shape action. I am wondering if this ability could be used again whenever the form is dropped to give the creature a massive effective health pool.  For example, if the Couatl used their action to Change Shape and become a Veteran, then was hit for enough damage to kill the polymorphed form, could it then re-use the Change Shape ability to transform into a fully healed Veteran once more? I'm aware there are been several similar questions, and some great answers with hints on how to prove this, for example  and .  But I've never really seen a detailed proof of the absolute convergence of the Riemann zeta function in the half-plane $\Re(s)&gt; 1$.  I hope there's interest on a detailed proof of this for reference. Here is my attempt. Please, fill in any detail that might be missing, or point out any mistake!  On $\Re(s)=\sigma&gt; 1$, we have  $$\sum_{n=1}^{\infty}\bigg|\frac{1}{n^s}\bigg|=\sum_{n=1}^{\infty}\frac{1}{n^\sigma}$$  and  $$\frac{1}{n^\sigma}\leq\frac{1}{n^{1+\epsilon}}$$  for any $\epsilon &gt;0$, so by the direct comparison test, if   $$\sum_{n=1}^{\infty}\frac{1}{n^{1+\epsilon}}$$  converges absolutely, then so do $\sum_{n=1}^{\infty}|1/n^s|$ and $\zeta(s)$.  By the integral test, the convergence of $\sum_{n=1}^{\infty}1/n^{1+\epsilon}$ is equivalente to the finitude of the integral  $$\int_1^\infty \frac{1}{n^{1+\epsilon}}=\bigg[-\frac{1}{\epsilon x^\epsilon}\bigg]=\frac{1}{\epsilon}$$  which holds for any $\epsilon &lt; \infty$.  Any correction or improvement is welcomed! Thanks in advance. How to stop constantly blinking Wifi LED? Can we get rid of the threshold of 15 chars for comments? I understand that there is an upper limit. But why do you have to type at least 15 characters to post a comment? It is easy to work around it anyway (like adding dots or other useless things). How well-known is the theology of Middle-earth, in Middle-earth? One thing that is notably absent in Middle-earth is any mention of temples, churches, priests or religious rites.  There are passing mentions of Men who would "worship" Sauron, but generally the world of Middle-earth seems much less religious than medieval Europe, or even classical antiquity.  One never hears about "the cult of Aule" or "the cult of Yavanna," although historically there were many "cults of Athena" or "cults of Poseidon."  Aragorn doesn't (to my memory) make an offering to Tulkas before battle, nor does he pray to Eru Ilúvatar for victory, and all the holidays and solemnities seem to commemorate historical figures, not religious ones.  This is especially strange in a world where there are still living witnesses, like Galadriel, to the actions of the Valar and other "divine" beings, and where there are still Maiar wandering around talking to people and putting on flashy firework shows.  Now, a lot of people talk about how Tolkien didn't want the Valar to be considered "gods," but at the same time he did use phrases like "the gods of old" numerous times.  Clearly, these beings would have qualified for worship in most cultures.  And even without the Valar being considered a true pantheon, there is still Eru, a closer analogue to the Christian God of Tolkien's beliefs, and we know the denizens of Middle-earth knew of him (Him?) because of the line "Eru, who in Arda is called Ilúvatar."  And yet, Ilúvatar seems not to be terribly important to anyone on a daily basis.  So my question is this: how familiar with the "theology" of Middle-earth were the citizens of Middle-earth?  Would the average merchant in Rohan know about the Valar and the Maiar and Iluvatar and the Music of the Ainur?  The average noble in Minas Tirith?  The younger Elves, like Legolas?  The Dwarf Lords?  Were the theological truths about the formation of the world, the Valar and the Maiar just so well known that they weren't worth commenting on, or had they been forgotten by most?  And if they had been forgotten, why wasn't the knowledge (whether through deliberate teachings or casual conversation) re-invigorated by witnesses like Gandalf or Galadriel? It is known that a superconductor is a material with electrical resistance zero. My question is, it is exactly zero, a theoretical zero, or for practical realistic reasons it is effectively zero? Generating a DEM and DSM from correct LiDAR point classification I have downloaded classified LAS data from    I am trying to generate accurate DEM and DSM for further analysis. I created a LAS dataset with a projected CRS of  NAD_1983_UTM_Zone_19N in meters and the z CRS in meters as well. My question is on which classifications do I choose for the DEM and DSM. Here is the filter options I have in my dataset:     According to unh LiDAR data report class 2 is ground.     What I have done so far:  DEM I chose the class 2 points and used the las dataset to raster.   DSM In the predefined settings I chose first return and used the las dataset to raster tool.   Is this an accurate way of generating these two rasters? Do I not have to take into account the the unassigned class 1, noise class 7, reserved 11, reserved 17, reserved 18?  Additionally (I can ask this as a separate question if it gets requested to), when using the las dataset to raster tool the sampling value is defaulted to 10. I would like to change it to 2 or 3 (would be meters) to match the LiDAR resolution. I also plan on using the generated DEM and DSM for a least cost path analysis and I want them to be higher resolution. Will making the sampling_value 2 or 3 throw off the results or should I leave it at 10? Why is the sum of two random variables a convolution? For long time I did not understand why the "sum" of two random variables is , whereas a mixture density function sum of $f(x)$ and $g(x)$ is $p\,f(x)+(1-p)g(x)$; the arithmetic sum and not their convolution. The exact phrase "the sum of two random variables" appears in google 146,000 times, and is elliptical as follows. If one considers an RV to yield a single value, then that single value can be added to another RV single value, which has nothing to do with convolution, at least not directly, all that is is a sum of two numbers. An RV outcome in statistics is however a collection of values and thus a more exact phrase would be something like "the set of coordinated sums of pairs of associated individual values from two RV's is their discrete convolution"...and can be approximated by the convolution of the density functions corresponding to those RV's. Even simpler language: 2 RV's of $n$-samples are in effect two n-dimensional vectors that add as their vector sum.           Please show the details of how the sum of two random variables are a convolution and a sum. cp vs. mv: which operation is more efficient? I find myself moving reasonably large amount of data (20+ GB) from one directory tree to other. Often times they are on the same filesystem but sometimes they are on different ones. I do cp just to preserve the original data just-in-case. Once the copy is done I delete the original data after verifying that the data has been copied alright. Sometimes I just do mv if I feel too lazy to clean original data afterwards. However, I am wondering, from purely technical point of view, which operation is more efficient? Why? Windows Starter Edition, Home and Home Premium do not include gpedit, how do I install it? I want to make some changes to Windows that require using the Group Policy Editor (gpedit.msc).  Unfortunately the Group Policy Editor is not included with the Starter Edition, Home and Home Premium editions of Windows.  How can I install it? I've had a very strange Finer error caused by recent macOS High Sierra betas that affected Macs running macOS 10.13 as well as macOS 10.12 Sierra. This error causes an entire Finder window to show visual artifacts when opening certain folders on either an APFS or HFS+ volume.  After moving the cursor or the affected Finder window, the window may look something like this;    Attempting to use Disk Utility to repair the affected volume does not resolve this issue, nor does restarting the affected Mac (even in Safe Mode).  Without formatting this disk, how can I prevent Finder from exhibiting this graphical error when opening particular folders? delayed addclass/remove class function not working Add Windows 10 to GRUB OS list I recently got a computer from school. It came with Windows 8.1 installed. I then installed another copy of Windows 8.1 (so it would use the built-in Windows Pro license) and upgraded it to Windows 10. I then installed Ubuntu alongside both Windows 8 and 10. Note that I made a separate 255MB ext2 partition for /boot. Now, when I boot the computer, I first see a GRUB prompt (I already un-hid the grub prompt 'cuz I like it that way) with Windows 8 and Ubuntu options. However, there is no Windows 10 option. If I select Ubuntu, the computer boots into Ubuntu. However, if I select the Windows 8 option, I then get sent to the Windows bootloader, where it then gives me options to boot either Windows 8 or Windows 10. (However, by this point, the computer has already loaded the kernel and all. Apparently Microsoft misunderstood the concept of a bootloader and decided that that meant &quot;boot practically the entire system before actually showing the bootloader&quot;. Typical Microsoft.) How can I disable the Windows bootloader and add a Windows 10 option to GRUB? EDIT: Someone has answered telling me to disable the Windows bootloader. However, I still do not know how to add Windows to the GRUB OS list. Can anyone help with this? EDIT 2: After removing Windows 10 from the Windows bootloader with EasyBCD, it seemed that, after a few reboots, it would continually unhide itself and Windows 10 would reappear. However, I then later deleted Windows 10 from the list of OSes in msconfig, and it seems to have stayed deleted. However, I STILL have not managed to get Windows 10 to appear in GRUB. It's as if GRUB simply doesn't detect it. Also, I'll put this in the question so that people see it - I have tried using boot-repair, however, it has NOT helped any. I have this rule in my iptables:  iptables -A INPUT -s 192.168.11.0/24 -j LOG   My question is:  Where is the iptables log file, and how can I change that? How to import sextante(processing) for QGIS 1.9 (2.0) Mount cifs Network Drive: write permissions and chown I have access to a cifs network drive. When I mount it under my OSX machine, I can read and write from and to it.   When I mount the drive in ubuntu, using:  sudo mount -t cifs -o username=${USER},password=${PASSWORD} //server-address/folder /mount/path/on/ubuntu   I am not able to write to the network drive, but I can read from it. I have checked the permissions and owner of the mount folder, they look like:  4.0K drwxr-xr-x  4 root root    0 Nov 12  2010 Mounted_folder   I cannot change the owner, because I get the error:  chown: changing ownership of `/Volumes/Mounted_folder': Not a directory   When I descend deeper into the network drive, and change the ownership there, I get the error that I have no permission to change the folder´s owner.  What should I do to activate my write permission? Limiting floats to two decimal points How can I include value of sharepoint's version column in a word document? Number of labeled trees which have one vertex of degree 4 How many labeled trees which have one vertex of degree 4 can we have? A tree with $10$ vertices has $9$ edges, so the sum of the degrees of the vertices is $2\cdot 9=18$. If there is one vertex of degree $4$, the sum of the degrees of the other $9$ vertices must be $14$. I don't know what to do next. Should I count all possible vertex degrees? Permanently mounting loop device I created a file   touch /datastore/virtual/pseudoblock   created a loop device with it  sudo losetup /dev/loop0 /datastore/virtual/pseudoblock   (although I got a warning about its size)  and then initialized it with random data  dd if=/dev/urandom of=/dev/loop0 bs=1M count=100   My questions are  a) why is it not displayed yet in my block devices' list?  NAME                     MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT sdb                        8:16   0 489.1G  0 disk   ├─sdb2                     8:18   0   488M  0 part  /boot ├─sdb3                     8:19   0 488.1G  0 part   │ └─sdb3_crypt           253:0    0 488.1G  0 crypt  │   ├─ubuntu--vg-root    253:1    0 472.2G  0 lvm   / │   └─ubuntu--vg-swap_1  253:2    0  15.9G  0 lvm   [SWAP] └─sdb1                     8:17   0   512M  0 part  /boot/efi sda                        8:0    0 931.5G  0 disk   └─sda1                     8:1    0 931.5G  0 part     └─sda1_crypt           253:3    0 931.5G  0 crypt      └─store--vg-store1tb 253:4    0 931.5G  0 lvm   /datastore   b) how can I permanently mount it via /etc/fstab since I cannot get its UUID?  $ blkid /dev/mapper/sdb3_crypt: UUID="fSHjbj-51K2-QfhI-G0Wb-o3lN-4pE1-BB4wCP" TYPE="LVM2_member" /dev/mapper/ubuntu--vg-root: UUID="9e452886-4d8g-fj54-854c-80bc171826e8" TYPE="ext4"   working on   $ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 16.04.5 LTS Release:    16.04 Codename:   xenial   with  $ uname -a Linux pkara-pc01 4.15.0-42-generic #45~16.04.1-Ubuntu SMP Mon Nov 19 13:02:27 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux