java.lang.NullPointerException Error
Why are my fields initialized to null or to the default value of zero when I've declared and initialized them in my class' constructor?
Searching for a tag across all Stack Exchange meta sites I want to find all questions tagged  on the meta sites of . Is there a better way than searching manually on each individual site? Installing 3rd party python libraries for QGIS on Windows Read it in the 90's. I remember one specific part where the inventor of the peeking mechanic has his Eureka moment, and has the presence of mind to give a thumbs-up/wave to the future, when they look back on his Eureka moment.  I also remember that they had computer screens that were like plastic cloth that they would just unfold on whatever surface was handy.  Sorry I don't have much more to go on.  Please and thank you! Selecting attribute values with html Agility Pack I'm trying to retrieve a specific image from a html document, using html agility pack and this xpath:  //div[@id='topslot']/a/img/@src   As far as I can see, it finds the src-attribute, but it returns the img-tag. Why is that?  I would expect the InnerHtml/InnerText or something to be set, but both are empty strings. OuterHtml is set to the complete img-tag.  Are there any documentation for Html Agility Pack? My desktop look is empty so all I have is a nice wallpaper. My Windows taskbar has the "Taskbar Appearance" setting to "Auto-hide the taskbar". Although hidden, it leaves a thin top layer so you can still see it a bit, and where the pinned shortcuts are. Is it possible to totally have it hidden without a trace? This is a serious question. It really bugs m. How do I change skins in minecraft pe? These questions are really bothering me. Any help would be much appreciated.  Let $p$ be prime  a) If $(G, \oplus)$ has order $2p$, prove that every proper subgroup of $(G, \oplus)$ is cyclic  b) If $(G, \oplus)$ has order $p^2$, prove that $(G, \oplus)$ has a subgroup of order $p$ What is the difference between g++ and gcc? What is the difference between g++ and gcc?  Which one of them should be used for general c++ development? Partition around bad drive sectors? I've seen a lot of hard drives with only a few bad (unrecoverable) sectors (as indicated by SMART). Of course the proper thing to do with a bad drive is replace it, as there's a good chance of the drive crashing completely in the near future; I'm aware of that. However, in the interim, or for those who don't want to spend $70 to save data they don't value highly anyway (sigh, non-technical people), or just to get some use out of old hardware instead of throwing it away, I'm wondering if there's a way to identify where the unrecoverable sectors are ("where" meaning numerically, from 0 to the number of sectors on the drive), so I could stick a blank partition in that general area. Yes, this would involve low-level-formatting the drive and reinstalling the OS, of course.  So:  Would partitioning around unrecoverable sectors even be a workable way of reducing the disk of losing data?  If so, is there a way to find the location of these unrecoverable sectors? How can I reset my Ability Points? I'm also curious about being able to reset my points, should I wish to change my ability configuration later.  So far (10h-ish) I've only seen one way, which is a potion sold by Kiera Metz for 1000g. However she's no longer available as a store, due to a story choice, so I'm not sure where else I could buy this potion.  Where might I buy this potion, and is it the only way to reset your ability points? Install Ubuntu from ISO image directly from hard disk of a system running Linux? How can I run blender from command line or a python script without opening a GUI? I'm interested in using Blender for producing images, 3d files, or calculating geometry on a server.  Can I make blender run a python script without opening a GUI?  If not, can I incorporate Blender's python API into my own python script without running a GUI? How to Remove URLs from Google Search Engine I have used so many things like url removal request and deleted the pages etc., but still the errors are shown in my webmaster tools.  How can I remove the urls completely from Google? How to completely uninstall and remove QGIS 2.8.1 on Windows Vista? I want to uninstall and completely remove QGIS installation from my computer(windows vista). I have uninstalled it and when i try to reinstall it says it is already installed on the system. In computer science we discuss an abstract machine called a "deterministic finite automaton". The standard initialism for this term is "DFA". This makes sense in the singular usage of the initialism.  However, the pluralization of the word "automaton" is "automata". One speaks of "an automaton" or "many automata". Consequently, it seems intuitive to form an initialism of the phrase "deterministic finite automata" as "DFA".   This does not seem correct, as "DFA" could be either plural or singular. On the other hand, "DFAs" also does not seem correct because it would seem to expand to "deterministic finite automatons", a phrase which no self-respecting computer scientist would ever utter.   This appears to be a duplicate of the question here   But that question was never clearly resolved. What to do? Add AD users to sudo group not working | CentOS 6.7 Playing system sound without importing your own We are in the combat phase:   I declared my attackers  My opponent declared his blockers, stating which attackers he was blocking I cast an instant, which automatically kills his blocker. There is nothing blocking my attacker now   Now we're in the damage phase. I said that my attacker now does damage and  reduces my opponent's hit points. My opponent said that because my attacker was blocked no damage could be done. I pointed out that the blocker was destroyed before the damage phase, so therefore he wasn't blocking, but he wasn't having it. (My attacker does not have trample)  Is this covered by a specific section in the rules? Is there any way of making a snow golem survive in hot biomes? Snow golems won't survive in the Nether (neither spawned in nor built ones). Is there a way to make a snow golem survive in the Nether and other hot biomes in vanilla Minecraft (i.e., without using mods)? Is the universe fundamentally deterministic?