"Could not find or load main class" Error while running java program using cmd prompt
What does "Could not find or load main class" mean?
Proving the so-called "Well Ordering Principle" I want to determine $$\lim\limits_{(x,y) \to (0,0)} \frac{x^2·y^3}{x^4+y^6}$$  I'm sure the limit exists, it's zero because I tried to find other different limits in line and parabola points ($(x,mx)$ and $(x,mx^2)$) but every time I got zero. So, I have to use the definition or sequences to confirm. I have learned about the correspondence of radians and degrees so 360° degrees equals $2\pi$ radians. Now we mostly use radians (integrals and so on)  My question: Is it just mathematical convention that radians are much more used in higher maths than degrees or do radians have some intrinsic advantage over degrees?  For me personally it doesn't matter if I write $\cos(360°)$ or $\cos(2\pi)$. Both equals 1, so why bother with two conventions? For example:  javac Foo.java Note: Foo.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. Tax considerations for selling a property below appraised value to family? I own a property that recently appraised for $350,000 in the state of Maryland that I purchased for $300,000 7 years ago. I wish to sell this property for a value of $240,000. Here are my questions:   Is this legal? The state of Maryland has a transfer/recordation tax of 1.5% for each, the buyer and seller. Would this be computed on the appraised or sale value? Will this pose any problem if the buyer needs financing? Would I be able to deduct a capital loss on my tax return?     From comments: I should have mentioned - the buyer is a sibling. Creating polyline-based "heatmap" from GPS tracks? This winter I am planning to track my downhill skiing/snowboarding using a GPS.  Most of my riding will occur at the same resort.  I would like to be able to create a sort of "heatmap" that shows the amount of runs that I have made in a given area.  As I add more and more GPS traces to my database, my goal would be to see a sort of linear heatmap of the most traveled areas.  Given the nature of downhill skiing, you would expect the uphill chairlift lines will be the "hottest" because it will be the only places visited over-and-over again.  Given that 1) my track will not be the same every time and 2) the area covered by following one "run" may be a few hundred feet wide, what might be the best way to analyze this "linear" data to create a sort of heatmap?  My thoughts were to buffer the lines, then intersect the polys to get a sort of Venn Diagram thing going.  My preference is to use open-source technologies.  I've got QGIS and PostGIS loaded and available.  UPDATE: In regards to @blah238's response, I was thinking of something that might be able to "collect" the number of passes ("runs") through an area, and then symbolize by the count.  Conceptually, this would be similar to ArcGIS "" (but for lines, not points) or  (but for multiple line in roughly the same area).  A more visual example of a similar concept might be a traffic-flow map, where highly-congested areas would equate to "highly-traveled" ski runs/areas:    I've read the following questions that may give some ideas, but they don't really address what I am trying to accomplish: tcpdump : lost packets What is your Instagram password when signing in using Facebook? Do this:   On your phone, create an instagram account using Facebook log in. Now on your desktop web browser, log in using Facebook connect.  Now go to delete your account - edit profile -> I'd like to delete my account.    It will ask for your password.   But you never gave it a password in order to create the account.   I tried using my Facebook password, but that didn't work.   Any ideas? The Instagram account management seems quite broken. How to change the light grey text that many web sites seem to use these days? Of late, I've noticed that many web sites seem to be using light grey text for many sections of their sites. Some such sections include - the text (link, usually) that shows in the status bar at the bottom of the browser when you hover the mouse over a link on their page, the indicator text in form fields to be filled in (e.g. the word "email" in the email address field), and many other elements on the page.  That light grey makes it much less readable.    Not sure whether is a new trend, or something to do with my browser settings (I haven't changed them lately, AFAIK), or Google Chrome, which is my browser. This is on Windows 7 running on a Dell Vostro laptop. I added the info about the laptop because I suspect the problem may even be due to my hardware settings, since I found the default brightness to be too high after I bought it, and changed it via Control Panel.  Would like to know what are some of the things I can check or change to solve this.  Thanks. Multiple domains for different products? I have a website with software applications. Is it good for SEO to choose one keyword rich domain name for each of our software products or should we stick to a single domain?  From a user's perspective I think it would be easier to remember a domain that is keyword rich as the user will instantly know what this product is for.  But I have read articles that the latest trend in SEO is to stick to one domain for all of your products and invest on this single domain website.  Is that true? What do you advise? Should I register a separate domain for each of our products or should I use only one single domain?  Should I do a 301 redirect with a .htaccess to a single domain? And what about the sitemaps? Should I register all sites in Google Webmaster Tools and post a separate sitemap for each one of them? should my main site sitemap include all pages or should separate domains have their own sitemaps? In biblatex, treat periods in journal as abbreviation dots I would like to consistently have a comma between the journal and volume number for article references using biblatex with biber as the backend. Unfortunately, the punctuation between the journal and volume is not consistent. Journals whose last word is abbreviated have no comma between the journal and the volume, and the word "Vol." is capitalized. Journals whose last word is not abbreviated have a comma and the word "vol." is not capitalized. I can fix the capitalization by un-commenting the commented lines in the below MWE, but the comma problem is quite perplexing. Apologies if this fix is in an answer somewhere, but I cannot find it (or at least, I don't know what to search for!).  Current output: [1] First Author. “Blah Blah 2”. In: Am. J. Phys. Vol. 72, no. 3 (Mar. 2004), pp. 367–375. [2] Second Author. “Blah blah”. In: Energy Fuel, vol. 27, no. 12 (Dec. 2013), pp. 7778–7789.  Expected output: [1] First Author. “Blah Blah 2”. In: Am. J. Phys., vol. 72, no. 3 (Mar. 2004), pp. 367–375. [2] Second Author. “Blah blah”. In: Energy Fuel, vol. 27, no. 12 (Dec. 2013), pp. 7778–7789.  MWE:  \documentclass{article} \usepackage{filecontents} \usepackage[     backend=biber,     citestyle=numeric-comp, ]{biblatex} \addbibresource{\jobname} % \DefineBibliographyStrings{english}{%     % volume = {\lowercase{v}ol\adddot}, % avoid capitalization after dots. % } \DeclareFieldFormat[article]{volume}{\bibstring{volume}\addspace #1} \DeclareFieldFormat[article]{number}{\bibstring{number}\addspace #1} \renewbibmacro*{volume+number+eid}{%   \printfield{volume}%   \setunit{\addcomma\space}%&lt;---- was \setunit*{\adddot}%   \printfield{number}%   \setunit{\addcomma\space}%   \printfield{eid}} \renewbibmacro*{journal+issuetitle}{%   \usebibmacro{journal}%   \setunit*{\addcomma\addspace}%&lt;---- was \setunit*{\addspace}%   \iffieldundef{series}     {}     {\newunit      \printfield{series}%      \setunit{\addspace}}%   \usebibmacro{volume+number+eid}%   \setunit{\addspace}%   \usebibmacro{issue+date}%   \setunit{\addcolon\space}%   \usebibmacro{issue}%   \newunit}  \begin{filecontents*}{\jobname.bib} @article{York2004, author = {Author, First}, journal = {Am. J. Phys.}, month = mar, number = {3}, pages = {367--375}, title = {{Blah Blah 2}}, volume = {72}, year = {2004} } @article{Baumgardner2013a, author = {Author, Second}, journal = {Energy Fuel}, month = dec, number = {12}, pages = {7778--7789}, title = {{Blah blah}}, volume = {27}, year = {2013} } \end{filecontents*}  \begin{document} \nocite{*} \printbibliography \end{document} Importing a Single Symbol From a Different Font Backup of clients' directory to Windows Server 2008 Is there anywhere within the Blender UI that displays the dimensionality &amp; bounding sets (e.g., all floats, floats in [0,1], floats in [0,255], etc) of arbitrary shader node inputs &amp; outputs?  I consistently find myself digging through stackexchange/the Blender docs/experimenting with less-than-equal-to to try to figure out what I need to divide by to normalize shader nodes' input/output values to within a specific range, or to center them at 0, etc. This seems like functionality that Blender's very rich UI might already have built into it, though, so I am wondering if I am just overlooking it somewhere.  As an example, I can do something like this, varying the threshold between 0, 0.5, and 1, and observing that in rendered view my sphere switches from all black to mixed black/white to all white, to convince myself that Blender's (Perlin) Noise Texture's Fac output naturally outputs floats in [0,1]:    But it seems odd that I should have to experiment, or search through docs or stackexchanges, to discover something like this. Is this information maybe already neatly displayed somewhere inside the Blender UI, and I just don't know where to look? How do I report a bug related to Stack Exchange? Does Stack Exchange contain any edit suggestion or bug submission system, or such type of discussion forum to inform SO or its administrators about suggestions and bug reports that relate to SO itself? A reward becomes a penalty if I am working to build a reinforcement agent with DQN. The agent would be able to place buy and sell orders for a day trading purpose. I am facing a little problem with that project. The question is "how to tell the agent to maximize the profit and avoid the transaction where the profit is less than 100$".  I want to maximize the profit inside a trading day and avoid to place the pair (limit buy order, limit sell order) if the profit on that transaction is less than 100$. The idea here is to avoid the little noisy movements. Instead, I prefer long beautiful profitable movements. Be aware that I thought using the "Profit &amp; Loss" as the reward.  "I want the minimal profit per transaction to be 100$" ==> It seems this is not something that is enforceable. I can train the agent to maximize profit per transaction, but how that profit is cannot be ensured.  At the beginning, I wanted to tell the agent, if the profit of a transaction is 50 dollars, I will remove 100 dollars, then It becomes a penalty of 50 dollars for the agent. I thought it was a great way to tell the agent to not place a limit buy order if you are not sure it will give us a minimal profit of 100$. It seems that all I would be doing there is simply shifting the value of the reward. The agent only cares about maximizing the sum of rewards and not taking care of individual transactions.   How to tell the agent to maximize the profit and avoid the transaction where the profit is less than 100$? With that strategy, what guarantee that the agent will never make a buy/sell decision that results in less than 100 dollars profit? Does the sum of reward - # transaction * 100 can be a solution? This is a very basic query I can't figure out....  Let's say I have a two column table like this:  userid  |  roleid --------|--------    1    |    1    1    |    2    1    |    3    2    |    1   I want to get all distinct userids that have roleids 1, 2 AND 3.  Using the above example, the only result I want returned is userid 1.  How do I do this? After using the simple LM317 on breadboard variable power supply for a while, a need for a more rugged and reliable bench power supply has arose.    Short on money, i decided to build it as many other amateurs like me did. The thing is that, for my current needs i don't need a giant digitally controlled multi-channel 500 watt beast or something like that.  Instead what i really want is a low wattage positive and negative low voltage ouput -12v-0v-12v for example. However i really like that my power supply to be safe, reliable and fool-proof as far as possible. So after searching the web here and there, i found many designs that from my point of view fell in one of two divisions:-   Ones that use discrete op-amps and transistors. And ones that use integrated voltage regulators.   So -at least for me- i think that the ones with discrete op-amps and transistors are more prone to malfunctions and issues compared to the integrated ones with all of their internal over current and thermal protection circuits which would need to be discretely implemented in the bench power supplies that utilize discrete op-amps, however those designs have the advantage of ease of customization and more importantly that it is easier to have 0V output compared to 1.2V in integrated voltage regulator ones.    So i like advice to help me choose between circuits that utilize discrete op-amps like this circuit for example:-  Or ones that use integrated voltage regulators with their intrinsic robustness and low form factor.    Also as a side but related question i have seen many designs on the web that utilize negative voltage fed to the adjust or like pins to achieve 0V output from integrated voltage regulators like this single positive power supply:-     Or a positive and negative channels power supply that i really like its design because of simplicity (not because of laziness but to avoid the drawbacks that may come with complex designs especially when implemented by an amateur like me):- And the question is      Is it wrong or a system safety and reliability lowering act to feed negative voltage to adjust pin for LM317 for example?     I ask this question because the datasheet clearly states that the working output range is 1.2V-37V for LM317 for example, also no similar circuit is mentioned in the Typical Applications section except for the following one:- And even in that circuit, however the adjust pin is tied to the negative rail, it does't regulate during this interval instead it is shut until the next half wave at least that what i understand.    So at last to sum it up which alternative is best suited for my needs, its pros and cons and suggested circuits if possible. Are commands complete sentences? seems to indirectly ask the question, but the upvoted answer says &quot;the actual sentence is...&quot;. So my question is this: Are commands considered to be grammatically sound, complete sentences in the English language? Some examples:  Go. Add a note. Do work. I'm a bit of a force.com IDE newbie - still learning. I'm trying to migrate a simple custom object (no fields) from one sandbox to another and I'm running into this error:  # Deploy Results:    File Name:    package.xml    Full Name:  package.xml    Action:  NO ACTION    Result:  FAILED    Problem: Cannot deploy InstalledPackage in Package Manifest with any other types!   Any help would be greatly appreciated.  Thanks!