I'm getting a NullPointerException for a java GUI for a warning message scenario if no data is added in GUI
What is a NullPointerException, and how do I fix it?
I have an ASUS K55VM and it came with DOS, and then Windows 7 was installed. I am planning to install Ubuntu on it. My computer had 4 partitions: 240GB, 230GB, 230GB, and 230GB, and I changed this to 5 partitions: 243GB, 230GB, 230GB, 150GB, and 80GB. I installed Ubuntu 12.04 to the 80GB partition through a USB flash drive. It installed fine, however the problem is during the Boot option in Windows Boot Manager. When I choose Ubuntu, this what is displayed:  Windows failed to start. A recent hardware or software change might be the cause. To fix the problem:   1. Insert your Windows installation disc and restart your computer.   2. Choose your language settings, and then click "Next,"   3. Click "Repair your computer." If you don't have this disc, contact your system administrator or computer manufacturer for assistance.    File: \ubuntu\winboot\wubildr.mbr   Status: 0xc000000e   Info: The selected entry could not be loaded because the application is missing or corrupt.   I tried to change the boot option for the OS and made Ubuntu as my first option. It worked, however Windows 7 does not show up in GRUB. In this fear I did the following:     Restarted my PC changed boot option 1 to Windows.   Formatted the drive to which Ubuntu was installed (80GB one) through Windows.   Restarted again.     The problem persists. Windows Boot Manager still shows Ubuntu, and when I choose this it gives two lines one like: grub rescue&gt;, but my Windows 7 is working perfectly fine.  Now I want a solution to remove Ubuntu from the Windows boot option and reinstall completely. How to draw arrows between colourboxes How often is $1+\prod_{k=1}^n p_k$ not prime? Recovering from forgotten lock pattern My son has an impression tablet 10 and has forgot the lock pattern. How can we reset it without knowing the code? Multiplicative inverse in $\operatorname{GF}(2^8)$? I know how to do multiplication over ${\rm GF}(2^8)$:  uint8_t  gmul(uint8_t  a, uint8_t  b) {     uint8_t p=0;     uint8_t carry;     int i;     for(i=0;i&lt;8;i++)     {         if(b &amp; 1)             p ^=a;         carry = a &amp; 0x80;         a = a&lt;&lt;1;         if(carry)             a^=0x1b;         b = b&gt;&gt;1;     }     return p; }   So, I tried to create a ${\rm GF}(2^8)$ multiplication table using this code. I've given below the values in the 3rd row of the table, but I don't think they're correct:      0  1  2  3  4  5  6  7   8  9  A  B  C  D  E  F 0 1 2   0  2  4  6  8  A  C  E  10 12 14 16 18 1A 1C 1E  3 . . E F   I don't know what went wrong. I built the table by multiplying the values in the first row with those in the first column.  E.g. in the third row, I multiplied 2 &times; 0, 2 &times; 1, &hellip;, 2 &times; E, 2 &times; F.  How can I create a multiplication table for arithmetic in ${\rm GF}(2^8)$?    Also, how can I find the multiplicative inverse of a number in ${\rm GF}(2^8)$?  For example, how can I determine that the inverse of 95 is 8A?  I tried to do this using the multiplication table above, but when I took 9th row and the 5th column in the multiplication table I got 2D, not 8A. Question. Let $M = \left\{ \begin{bmatrix} a &amp; b \\ -b &amp; a \end{bmatrix} \,\middle\vert\,  a, b \in \mathbb R \right\}$.  Show that $(M,+)$ and $(\mathbb C,+)$ are isomorphic.  Show that $(M^{*},*)$ and $(\mathbb C^{*},*)$ are isomorphic.    (Here, $M^{*}$ is defined as excluding the zero-element) I understand that there exists an isomorphism $\phi:M \rightarrow\mathbb C$ defined by $\begin{bmatrix} \alpha &amp; \beta \\ -\beta &amp; \alpha \end{bmatrix}\mapsto \alpha+i\beta$, ie. I can show that $\phi(M_{1}+M_{2}) = \phi(M_{1})+\phi(M_{2})$ and $\phi(M_{1}*M_{2}) = \phi(M_{1})*\phi(M_{2})$. However, I'm unsure how to go about the two subquestions seperately. Quick easy way to migrate SQLite3 to MySQL? What uses are there for "placement new"? The set of real numbers and power set of the natural numbers I have learnt that the cardinality of the power set of the natural numbers is equal to the cardinality of the real numbers. What is the function that gives the one-to-one correspondence between these two sets?  I have also learnt that there exists no set whose cardinality is strictly between the natural numbers and the real numbers. Is there a proof of this or at least some intuitiveness behind it? Is there an easy way to attach source in Eclipse? I'm a big fan of the way Visual Studio will give you the comment documentation / parameter names when completing code that you have written and ALSO code that you are referencing (various libraries/assemblies).  Is there an easy way to get inline javadoc/parameter names in Eclipse when doing code complete or hovering over methods? Via plugin? Via some setting? It's extremely annoying to use a lot of libraries (as happens often in Java) and then have to go to the website or local javadoc location to lookup information when you have it in the source jars right there! I need your help with references. I have 1 main reference section, and I want to include a second list of references as an appendix. For the main reference I use:  \newpage  \bibliographystyle{plainnat}  \bibliography{library}   The problem is that I don't know how to include the second list using a different bib file, and then calling the function \nocite{*} to show every sources inside the file.   I have the appendix part workout. I need your help to design the function to call the second bibliography, and that does't interfere with the main reference:   \newpage  \appendix  \section{Other Sources} \label{app:ReferencesB}   In addition, I will prefer that the word References is not shown after Other Sources.  Thank you so much!! Remove items from one list in another Will links to images be kept permanently when added to a comment and nothing else? I assume, that Stack Exchange have some clean-up subsystem, which deletes all "abandoned" images (stored at i.stack.imgur.com), that is, all of them, that were initially uploaded, but no post is actually having link to them. Am I right?  If such subsystem is implemented and is doing its job on regular basis, then what about following scenario:   Start a new question or answer, anywhere. Hit button and upload an image. Copy generated image's URL  to clipboard. Close tab and drop editing post. Go to question on answer, you actually planned to reply. Post a comment to it and paste copied image's URL from clipboard to comment's body.   Will uploaded image, with URL pasted only to comment, be kept permanent? Does clean-up subsystem (if exitst) take care of checking for image's URLs in comments as well? Why do we need sigma-algebras to define probability spaces? Sometimes we read books rather quickly and don't give them much (or any) thought, so the action 'reading' does not necessarily imply that we have given enough thoughts to any book we read.   Is there a word that describes reading a book with great care; usually but necessarily slowly over a long period of time. While browsing Stack Overflow, I noticed that I lost a lot of reputation:        Is this serial downvoting? Will it be corrected by a rep-recalculation? How often are those done?    Here's a second instance: Do tag edits count for Archaeologist? How do I find the files installed by a particular package? Where is the .deb file to look at? I have installed pulseaudio-module-bluetooth using apt.  $ type pulseaudio-module-bluetooth bash: type: pulseaudio-module-bluetooth: not found $ which pulseaudio-module-bluetooth $ whereis pulseaudio-module-bluetooth pulseaudio-module-bluetooth:   Clearly, I'm looking for the wrong thing.  The package does not simply install a command that is the same name as the package.  Alright, then.  I want to find out what all commands (or executables) this package installed, and their locations.  The answers to "" tell me how to find the files installed by the package if I have a .deb file.  I'm not installing directly from a .deb file, though.  I'm using apt.  Where is the .deb file that that used?  Is there a copy on my system somewhere that I can query with the commands in the answers to that question?  Where?  If there isn't a local copy on my system, can I get one with apt?  How?  Is there some handy apt (or similar) command that wraps this up for me, so that I do not have to run dpkg-deb directly?  What is it?  Can I find the package's file list entirely on-line, without explicitly downloading any .deb files and before installing anything with apt?  How? What is the maximum number of Locations Discovered that one can achieve in Skyrim? How to use Cubic to create a custom Ubuntu live CD image?