Getting java.lang.NullPointerException while entering data into database in jsp using ojdbc
What is a NullPointerException, and how do I fix it?
I'm using Bash on both client and server. When running a command over SSH:   ssh &lt;host&gt; 'declare' gives a list of shell variables. ssh &lt;host&gt; 'mount' gives a list of mountpoints.   However, declare is a Bash builtin, while mount is an external command. How does SSH know which to run if there is a shell builtin and an external command with the same name on the server? "who" vs. "whom" and when to omit the relative pronoun This is the boy who was asked by the teacher to stay back after school. This is the boy whom the teacher asked to stay back after school. This is the boy the teacher asked to stay back after school.   Are the sentences above correct ? Eclipse is giving me this error when I try to copy an object back to the Force.com server: "unable to perform synchronize check with remote server Invalid username, password, security token; or user locked out Your project may be out of sync."  This is my first try at using Eclipse, so it may not be set up right.  Can anyone help?  Thanks!  Edit: screenshot of trying to deploy: Profile page "activity" tab is broken Does an electrolytic capacitor degrade each time it receives reverse voltage? Why don't shell builtins have proper man pages? All shell builtins share the same manual page:  BUILTIN(1)                BSD General Commands Manual               BUILTIN(1)  NAME      builtin, !   etc.   Then there is a little text describing what shell builtins are, and then a list that  looks something like this:    Command       External    csh(1)    sh(1)        !             No          No        Yes        %             No          Yes       No   But if we do man grep we get sections such as   Bugs History See also Standards Description   etc.  Don't shell builtins have their own history, description and arguments like -A or -r? Why isn't that provided in the manual pages and how would I learn to use them correctly and efficiently? how many terms will there be once you collect terms with equal monomials? What is the sum of all the coefficients? I'm using Ubuntu Maverick and Virtual Box 3+. I have Windows 7 Ultimate. The problem is that it doesn't detect USB drives in Windows 7, but USB peripherals (mouse + keybord) are working.  I followed , but I can't find the user group vboxusers. How can I continue? I would also like to upgrade to the latest version without any risk (without losing my virtual hard disk drive). Automatically make various multiple stroke colour the same as various underlying fill colours. I have auto traced a photograph in illustrator - its got thousands of vectors once I expand it and illustrator has converted each of them to a filled colour - I want to now trace the edges of them with a grungy brush but using the underlying fill colour. Where in illustrator can I stroke or outline these fills using the underlying colour - surely this is something that the program automatically does?   I've found this script online but don't know how to implement it. I'm new to this so any help appreciated. Many thanks.   James   var idoc = app.activeDocument;   var sel = idoc.selection;    for (i=0; i&lt;sel.length; i++) {       var ipath = sel[i];       ipath.stroked = true;       ipath.strokeColor = ipath.fillColor;   } We are given with  $$S_n=\{(x,y)|x^2+y^2=n, \text{where }x,y,n \in \mathbb Z\text{ and }n\geq0  \}$$ Now observe that $-\sqrt n\leq x\leq\sqrt n $ and similarily, $-\sqrt n\leq y\leq\sqrt n $. This means that $-\left \lfloor{\sqrt n}\right \rfloor\leq x\leq \left \lfloor{\sqrt n}\right \rfloor$ and  $-\left \lfloor{\sqrt n}\right \rfloor\leq y\leq \left \lfloor{\sqrt n}\right \rfloor$. Through this result one can easily write code and figure out the cardinality of set $S_i$ but I was wondering whether an expression can be found that would allow one to directly compute $|S_i|$. $\infty = -1 $ paradox JavaScript OR (||) variable assignment explanation How to exit early on pipe close? I use golang for writing programs that are too complex to express as bash functions. The programs read stdin line by line and write modified output to stdout.  The problem with this iterating over all the lines in stdin approach, is that it doesn't exit early. For example, the following command will process all the lines instead of just 10:  cat largefile | custom-program | head -n 10   How do the native unix application manage to exit early and how can I do the same in my custom scripts? More Question Filtering options I realize that this may be a big request, but...  I think that instead of tabs on the recent question activity pages, or more likely as a new tab, adding a more advanced filtering option.  For instance, being allowed to exclude tags, filter by accepted answers or not, and, most importantly, being able to combine multiple filters!  E.g.: Filtering posts with tag Javascript without tags Jquery and AngularJS with no accepted answers and a score >= 0.  I feel like this is a biggish change that, if implemented as a new tab, wouldn't be that hard to implement, but would be very useful. Update to latest version of java after ppa is discontinued On the Goblet of Fire Barty Crouch exactly got Mad-Eye's voice when he transformed into him, but on the Deathly Hallows, they were all able to have their own voices instead of Harry's. Why is the effect of the polyjuice potion inconsistent? Eigenvalues and power of a matrix proof that on a compact manifold a vector field is complete I would like to know if my proof of the following statement is correct     If $M$ is a compact manifold, then every vector field $X$ over $M$ is complete.   Proof:  I take $p\in M$ and $(\gamma_p,I_p)$ a maximal integral curve through $p$. $I_p$ is open and non empty so if $I_p$ is closed, it is equal to $\mathbb{R}$.  So take $s\in \text{Adh}(I_p)$. There exists $t_i\rightarrow s, t_i\in I_p$. Define $q$ as $\text{lim}(\gamma_p(t_i))$ and take a maximal integral curve passing by $q$ as $(\gamma_q,I_q)$. Then since the vector fields are $C^\infty$, $\gamma_q(I_q)\cap\gamma_p(I_p)$ is nonempty (intuitively, this is clear but don't really know how to show it).  On the intersection, $\gamma_p$ and $\gamma_q$ coincide. So we can extend the maximal curve $\gamma_p$ to include $\gamma_q$. This implies that $q\in\gamma_p(I_p)$ and is actually equal to $\gamma_p(s)$  I think the main idea is there even though it probably lacks a bit of rigour. Limit point versus limit and implications for convergence I understand that similar questions to this have been asked  and  but I believe my question is different because with regards to (1) I am not asking about the set $X$ that contains the points of my sequence and with regard to (2) because I have the distinct definitions of limit and limit point in mind. That said:  My Question: My textbook, Fundamental Ideas of Analysis by Michael Reed, defines a limit point as:     Definition: Let $(a_n)$ be a sequence of real numbers. A number $d$ is called a limit point if, given $\epsilon &gt; 0$ and an integer $N$, there exists $\color{red}{\mathrm{ an }} \ n \ge N$ so that $|a_n - d| \le \epsilon$.    The definition of a limit is as follows:     Definition: We say that a sequence $(a_n)$ converges to a limit $a$ if, for every $\epsilon \ge 0$, there is an integer $N(\epsilon)$ so that $|a_n - a| \le \epsilon \color{red}{\text{  for all  }} n \ge N$.    From these definitions, and given this question:     If a sequence converges it has exactly one limit point. Is the converse true? If not, provide a counterexample   Can I conclude that the converse is indeed true simply by appealing to the definitions, or do I need a tighter proof. And if I do, I'm a little stuck on how to refine this proof. Seven-sided dice from five-sided dice with finite rolls I have a 5-sided dice, and I want to use it to simulate a 7-sided dice. Is there a way to do this with a finite number of rolls?