Array Null Pointer Exception
What is a NullPointerException, and how do I fix it?
Why can't I pass the table name to a prepared PDO statement?  $stmt = $dbh-&gt;prepare('SELECT * FROM :table WHERE 1'); if ($stmt-&gt;execute(array(':table' =&gt; 'users'))) {     var_dump($stmt-&gt;fetchAll()); }   Is there another safe way to insert a table name into a SQL query? With safe, I mean that I don't want to do  $sql = "SELECT * FROM $table WHERE 1" What can primes, except 2, 3, and 5, be congruent to $\pmod {30}$? After some trials, I found out that a prime $p \gt 5$ is congruent to $q\pmod{30}$, where $q$ is also a prime, and $1 \le q \lt 30 \;$ (i.e.  $p \equiv q\pmod{30}.$  Is there a way to write a formal proof to show this?  Is that an acceptable answer. After one of the latest updates (not sure if it was the last one or a previous one) of the Google Play app, I am having an error trying to update a large app (42MB). It says:     Error Downloading . There is insufficient space on the device.   My device is a Samsung P1000 running Froyo. It's rooted, but the error was there before rooting it.  A quick Google search showed several Samsung users having the same problem (the app in question that was giving me the headache is Smurf's village). Some said that removing the updates to the Android Market (Google Play) app would fix it, but to me it was of no avail.  I also tried the procedure in  to no avail.  Now I am stuck with a prehistoric version of the Market (that works on small apps) and still cannot update Smurf's Village or install big apps. How can I fix this?  EDIT: device has over 2GB of internal SD storage, 27GB of external SD card, so space is not an issue. Why do my LED lights stay on, even when the switch is off? Update 02/02/2019 I appreciate all the responses and help but unfortunately i must have not seen the emails stating there were responses! I am now looking into a NEST thermostat and was curious if they too, use the same connections. Lastly, looking for a quick recommendation on which WiFi Compatible therms are preferred by the memebers that respond! Thanks again your knowledge is highly appreciated! Bob  I Purchased the Honeywell WiFi Prog Thermostat to replace my Round Digital Honeywell Thermostat. I have separate Heating and Cooling (Heating is a Weil McLain Boiler for Hot water baseboard and Hot water(no tank) and Cooling is a separate unit that was added later.)  Wires:  RC Cool R Heat W Heat Y Cool G Cool   3 wires from AC unit and 2 from Heater.  If I were to go the separate transformer route to power the thermostat, where would I land the 2 wires?  C and ??? Debug a java application without starting the JVM with debug arguments Normally to attach a debuger to a running jvm you would need start the jvm with arguments such as the following:  &gt; java -Xdebug -Xrunjdwp:transport=dt_socket,address=1000,server=y,suspend=n   Now if I want to debug a process that wasn't started in debug mode, what can I do?  This situation arrises when a production system (i.e. started without debug args) exhibits a 'random' (I use the term loosely) bug. So I can't restart the jvm with the appropriate arguments, because nobody knows how to reproduce the bug again. Is it impossible to attach to the JVM in this situation?  Just to clarify it is not possible to use tools like jdb to attach to already running JVMs unless they were started in debug mode  from the JVM man page     Another way to use jdb is by attaching it to a Java VM that is   already running. A VM that is to be   debugged with jdb must be started with   the following options: Limit of a particular variety of infinite product/series How do I hide javascript code in a webpage? A rubber viewfinder cover is connected to my camera strap.  What's it for, and when do I use it?  What happens to a photo if I don't use it? Editing capabilities document in GeoServer I've got several layers in GeoServer, one of which I'm trying to use as a WMS in desktop programs (Manifold 8). I've set it up correctly, but whenever I bring it into Manifold, it projects the layer into EPSG:4326, which unfortunately can't work with my map - I need it in EPSG:3857. The layer in question is wrapped inside a more overarching layer definition, which contains all the layers - and coordinate systems that allow them all to be used flexibly. However, I want to put this layer on its own in the capabilities document, and only allow it to use EPSG:3857. How, in GeoServer, would I edit, or override, a capabilities document? If I roll 2d8 and 1d6 for damage, how many "damage rolls" is that? 1, 2, or 3? How can I change my default text editor from gedit to Emacs? Suspended user cannot award bounty I asked a question on Stack Overflow: . I want to award my bounty to  by user  However, my Stack Overflow account is suspended recently for 7 days, and the suspension still has 5 more days to end.And I know I can't vote, ask, answer or comment as pointed on  by  with the sentence below.  You will be unable to vote, ask, answer, or comment.  I couldn't find anything about not being able to accept an answer or award bounty so I tried to accept the mentioned answer above and award my bounty to it and I got a  Suspended users cannot vote  rejection which can be seen below with a screenshot.  I know this  If you do not award your bounty within 7 days, the highest voted answer created after the bounty started with at least 2 upvotes will be awarded half the bounty amount.  from . None of the answer given to my question is upvoted and the answer I mentioned is not the oldest one after the bounty started so it won't be awarded by community. What can I do? (except being a good guy and not get suspended :)) JavaScript variable definition: Commas vs. Semicolons How do I make the Messages that are sent to me stop going to my Mac? Outlook: scheduling recurring out-of-office? In Outlook, is there a way (or an add-on that can do it) to schedule a recurring out-of-office message?  I work 4 10's, so I'm out of the office every Monday, and it's a bit of a pain to have to reset my out-of-office message every single week. I need to show the following: $$\lim_{k\rightarrow \infty} \left(1 + \frac{z}{k}\right)^k=e^z$$  For all complex numbers z. I don't know how to start this. Should I use l'Hopitals rule somehow? To hyphenate or not? We have added JSON-LD structured data to our website, so Google knows information about our company (company name, url, logo, address, etc.). We worked from the template on Google's .  One thing I couldn't find an answer to is where exactly should this JSON-LD snippet be included on our website? Right now, I only have it on our home page. I didn't know if it would look bad to search engines to have the Organization markup on every single page. But is there any recommendation?  Should Organization markup about our company be included on every page or only on certain pages? Help Me Understand My Bicycle's Gears