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Java Forum / General / January 2007What are com.blah or org.blah?
Whenever I look at an open source code, I see people write com or org in their import section. i.e. import com.blah.blah import org.blah.blah What do they stand for? Is it a conventional thing? > Whenever I look at an open source code, I see people write com or org > in their import section. [quoted text clipped - 3 lines] > > What do they stand for? Is it a conventional thing? The convention is to base your package names on your domain name. The idea is to avoid naming collisions. For example, nobody but me should write a class in the org.uncommons.* namespace, so there should never be another class with the same fully-qualified name as mine. This means my classes should be able to mix classes from other libraries without the possibility for naming problems. Dan.  SignatureDaniel Dyer http://www.uncommons.org >> Whenever I look at an open source code, I see people write com or org >> in their import section. [quoted text clipped - 10 lines] > means my classes should be able to mix classes from other libraries > without the possibility for naming problems. Unfortunately, whoever cooked up this convention was obviously somewhere corporate, where everyone and his brother makes $70,000+/year and they can all afford to own their own domain names. Apparently in the utopian workers paradise where noone ever gets laid off and has to let their $whatever/month business-class Web hosting lapse or face starvation, at that. And, of course, didn't bother to think up a convention for the rest of us (tm), us joes who have a consumer broadband account and some page on Yahoo or Myspace or even, if we're lucky, at www.ourisp.com. But do we really want to be making huge numbers of com.myspace.MyClass classes? Somehow I think that defeats the purpose. :) Has anyone come up with any good alternatives for Java developers without any domain names to call home? I've seen a few use org.sourceforge.<projectname>.subpackages-if-any.Foo when they have an actual sourceforge project, but that's also not exactly universally-applicable... I suppose you could use com.myspace.<username-at-myspace>.Foo ... :) > >> Whenever I look at an open source code, I see people write com or org > >> in their import section. [quoted text clipped - 31 lines] > > :) You think you're funny don't you? :-) Actually, I'd be amazed if you could afford a java-development computer and NOT afford a $35/yr domain name. No one said you had to have a website, just a domain :-) - Daniel. P.S. I host my own sites :-) Not a big deal. >> Has anyone come up with any good alternatives for Java developers >> without any domain names to call home? I've seen a few use [quoted text clipped - 11 lines] > and NOT afford a $35/yr domain name. No one said you had to have a > website, just a domain :-) Domains are getting cheaper all the time. You can get a .com for £8 ($15 US) or a .co.uk for £2.95 a year. Even if that is out of reach, you can probably come up with package names along similar lines. If you host your project on java.net or sourceforge.net you have a ready-made sub-domain. If you are a student you can use your university or college's domain combined with your user account name, e.g. <university.domain>.<department>.<username>. Dan. SignatureDaniel Dyer https://watchmaker.dev.java.net - Evolutionary Algorithm Framework for Java > ...you can probably come up with package names > along similar lines. If you host your project on java.net or > sourceforge.net you have a ready-made sub-domain. If you are a student > you can use your university or college's domain combined with your user > account name, e.g. <university.domain>.<department>.<username>. And if all else fails, perhaps 'ind' for 'individual'.. ind.thompson.andrew.MyClass (though that is a stupid name, for a class) Andrew T. >>...you can probably come up with package names >>along similar lines. If you host your project on java.net or [quoted text clipped - 9 lines] > > Andrew T. I suspect more than one individual Andrew Thompsons exists today and more might exist in the future. So that doesn't seem like a great scheme. Registering a domain for the price of a cup of coffee or two seems a reasonable deal for anyone needing to publish Java classes to the world at large. When I first registered a .com domain, nic.ddn.mil let you have them for free :-) .. > > And if all else fails, perhaps 'ind' for 'individual'.. > > > > ind.thompson.andrew.MyClass .. > I suspect more than one individual Andrew Thompsons ... 1) A microbiologist from the UK 2) A Canadian parliamentarian who was ordered to show his presence before the parliament or risk dismissal (never followed up what became of him) 3) ..many others. Screw 'em. They ain't Java coders, and any other Java coder with the same name would be accused of impersonating me, should they be silly enough to use that package name (..by me, anyway). (Though they might add a real, or arbitrary, middle name, if they really want to go that way..) >...exists today and > more might exist in the future. So that doesn't seem like a great scheme. > > Registering a domain for the price of a cup of coffee or two seems a > reasonable deal for anyone needing to publish Java classes to the world > at large. Domain names can be 'stolen'.. (just as identities can). Six of one, half a dozen of the other.. Andrew T. >>>...you can probably come up with package names >>>along similar lines. If you host your project on java.net or [quoted text clipped - 12 lines] > I suspect more than one individual Andrew Thompsons exists today and more > might exist in the future. So that doesn't seem like a great scheme. The amount of effort to make your packages globally unique should be proportional to the likelihood that they will ever need to be globally unique. > >>>...you can probably come up with package names > >>>along similar lines. If you host your project on java.net or [quoted text clipped - 16 lines] > proportional to the likelihood that they will ever need to be globally > unique. If you are losing all your hair worrying about this, then why not just randomly draw a number from 0,2^128. The probability of a collision is extraordinarily low. > If you are losing all your hair worrying about this, then why not just > randomly draw a number from 0,2^128. The probability of a collision is > extraordinarily low. Or use the MAC address of (one of) the network adaptors in your computer (I realise that not everyone /has/ a computer, but...). -- chris >> If you are losing all your hair worrying about this, then why not just >> randomly draw a number from 0,2^128. The probability of a collision is [quoted text clipped - 4 lines] > > -- chris and why not use your bank account number? this one is unique for sure and you the least you can even expect is some guy gives you money!!! > >> If you are losing all your hair worrying about this, then why not just > >> randomly draw a number from 0,2^128. The probability of a collision is > >> extraordinarily low. > > > > Or use the MAC address of (one of) the network adaptors in your computer (I > > realise that not everyone /has/ a computer, but...). Yeah, but what if I sell the computer. Then I have to refactor. What a pain. I think it would be better to use a number based on your DNA. > > -- chris > > and why not use your bank account number? this one is unique for sure > and you the least you can even expect is some guy gives you money!!! To guarantee uniqueness, you should include your PIN. Make sure to email me both numbers so I will not mistakenly use them in my java projects. > > >> If you are losing all your hair worrying about this, then why not just > > >> randomly draw a number from 0,2^128. The probability of a collision is [quoted text clipped - 5 lines] > Yeah, but what if I sell the computer. Then I have to refactor. What > a pain. I think it would be better to use a number based on your DNA. I've got it. Everyone who owns a MAC address can have a java domain of the form mac.${MACADDRESS}.${TIMESTAMP} where ${MACADDRESS} is their respective MAC address and ${TIMESTAMP} is the Unix timestamp of some date in which they owned the MAC address. Advantages: Most people can have many more domains than they would ever use. If they sell the MAC address, the new owner will not collide with them. Disadvantages: Some people don't own and have never owned a MAC address. We would have to get ICANN to promise never to release mac as a TLD. Defective clocks could cause collisions. > > > -- chris > > [quoted text clipped - 4 lines] > email me both numbers so I will not mistakenly use them in my java > projects. > I've got it. Everyone who owns a MAC address can have a java domain of > the form > mac.${MACADDRESS}.${TIMESTAMP} > where ${MACADDRESS} is their respective MAC address and ${TIMESTAMP} is > the Unix timestamp of some date in which they owned the MAC address. Nice ;-) -- chris > Actually, I'd be amazed if you could afford a java-development computer > and NOT afford a $35/yr domain name. No one said you had to have a > website, just a domain :-) The latter is a *recurring* cost, however, and what good is a domain without a website worthy of a separate domain? Oh -- naming your Java packages. Of course, that amounts to a defacto $35 annual license renewal fee for using supposedly free development tools, I hope you realize... unless of course you say screw it and just use a made up name unlikely to be duplicated by anyone else. I hate to contemplate the amount of refactoring that's needed for any project still in use when the original domain lapses for whatever reason to keep it in compliance. Even using Eclipse. And remember, software is ALWAYS still in use long after everyone planned for it to be. That means after the domain is sunsetted, after anything else is ... etc. Is the domain namespace really scarce enough to justify not handing freebies out to everyone in the world, their dog, AND their organization for that matter? Charging a not-insignificant (and recurring!) fee for a non-scarce thing like an identifier smacks of capitalism run amok. It amounts to an online property tax, being levied by private business, on the online equivalent of land holdings. What ever became of the good ol' days of fighting violent, bloody wars in miserable weather in the name of things like "no taxation without representation!"? :P > > Actually, I'd be amazed if you could afford a java-development computer > > and NOT afford a $35/yr domain name. No one said you had to have a > > website, just a domain :-) > > The latter is a *recurring* cost, however, and what good is a domain > without a website worthy of a separate domain? It makes no difference how you name your packages if they are only used within your own organisation (living room, whatever). The only constraint is that you avoid "inbound" clashes (as it were) which you can do by, say, putting all your stuff under "local" (local.mystuff.whatever) since "local" isn't a TLD and is unlikely to become one. If, on the other hand, you /do/ want to make your code more generally available then you almost certainly are going to put it somewhere with an associated global URL -- in which case you can use that for the root of the package names. -- chris > It makes no difference how you name your packages if they are only used within > your own organisation (living room, whatever). The only constraint is that [quoted text clipped - 4 lines] > somewhere with an associated global URL -- in which case you can use that for > the root of the package names. In fact, the use of non-standard TLDs solves the "people's rights against the fatcat capitalists!" rave. You only have to pay for domains under ICANN hegemony, and then only if you intend them to be visible on the 'Net. You are not forbidden to use, say, 'com.exxon.whatever' for your own package names, except insofar as you publish them in a way that conflicts with someone's intellectual property or trademark rights. But 'folk TLDs' avoid even that problem. You could even use your name itself as a domain: doe.john.m.somepackage or we could as a society agree that 'local' or 'indiv' or some such is the global free TLD, and just risk collisions. After all, if by some fluke both John M. Q. Doe, IIIs wrote Java(tm) code, what are the chances that their package and class names will collide in the same project? If it did in my project, I'd probably contact both Does to ask their help. package indiv.doe.john.m.q.iii.somepackage; - Lew > It makes no difference how you name your packages if they are only used within > your own organisation (living room, whatever). The only constraint is that [quoted text clipped - 4 lines] > somewhere with an associated global URL -- in which case you can use that for > the root of the package names. Then you get into the problem of ensuring that that URL continues to belong to your software for as long as the software remains in use. It's very hard to get any kind of stable Web hosting at all on a budget nowadays ("stable" as in "url doesn't change -- ever"). Probably you also want the javadocs to be hosted stably for others to link to. Why isn't there a good, free Web host these days, let alone one with staying power that doesn't rearrange things internally on its own? It seems you're artificially constrained to three options -- keep your software entirely private, use an existing open source hosting site like SourceForge, or go commercial *and be successful*. Anything else means paying for hosting out of your own pocket, *on top* of whatever you already pay for network access (shouldn't hosting of at least a small to medium amount of data at a stable address be included as basic network access? But it's not...) and that means you'll be paying to keep your Java online and legitimate for a lifetime (its or yours). So much for "free", even as in beer... > > Actually, I'd be amazed if you could afford a java-development computer > > and NOT afford a $35/yr domain name. No one said you had to have a [quoted text clipped - 23 lines] > days of fighting violent, bloody wars in miserable weather in the name > of things like "no taxation without representation!"? :P Actually, Domain names used to be "free" if you hosted your own DNS servers, and Diamonds are a very non-scarce, but quite expensive. > Has anyone come up with any good alternatives for Java developers > without any domain names to call home? Just use whatever you deem unique for you. The use of the domain name is a convention, not enforced in any way, but is the package naming convention least likely to generate collisions when someone else uses the classes. For code that lives just in your system, use whatever you want. Counterexample: Microsoft early on used the package structure "com.ms.*" even though they didn't have the "ms.com" domain; presumably "ms" was easier to type for lazy Redmond programmers than "microsoft". :P > Counterexample: Microsoft early on used the package structure > "com.ms.*" even though they didn't have the "ms.com" domain; And ms.com was a real domain at the time too -- for yet another dose of corporate arrogance. I seem to recall that it was owned by some law firm at the time (a very vague memory), although it's owned by Morgan Stanley now. I agree, though, that the package naming convention is better viewed as a very sensible guideline, than as a Rule Which Must Never Be Broken. -- chris >>Counterexample: Microsoft early on used the package structure >>"com.ms.*" even though they didn't have the "ms.com" domain; [quoted text clipped - 5 lines] > I agree, though, that the package naming convention is better viewed as a very > sensible guideline, than as a Rule Which Must Never Be Broken. Agreed. In fact, given the choice between paying an additional $35 a month for life to "rent" my package name root or breaking the convention, I'll pick breaking the convention -- especially on my current income, which is not particularly stellar (under $20K/year USD)... > Agreed. In fact, given the choice between paying an additional $35 a > month for life to "rent" my package name root or breaking the > convention, I'll pick breaking the convention -- especially on my > current income, which is not particularly stellar (under $20K/year > USD)... A fair point but, just to be clear, it's not per month - $35 will get you 2 years. Dan. SignatureDaniel Dyer http://www.uncommons.org "yaru22" <yaru22@gmail.com> said: >Whenever I look at an open source code, I see people write com or org >in their import section. [quoted text clipped - 3 lines] > >What do they stand for? Is it a conventional thing? They're packages; please see the Java Tutorial at Sun: http://java.sun.com/docs/books/tutorial/java/package/packages.html and http://java.sun.com/docs/books/tutorial/java/package/namingpkgs.html SignatureWolf a.k.a. Juha Laiho Espoo, Finland (GC 3.0) GIT d- s+: a C++ ULSH++++$ P++@ L+++ E- W+$@ N++ !K w !O !M V PS(+) PE Y+ PGP(+) t- 5 !X R !tv b+ !DI D G e+ h---- r+++ y++++ "...cancel my subscription to the resurrection!" (Jim Morrison) > Whenever I look at an open source code, I see people write com or org > in their import section. [quoted text clipped - 3 lines] > > What do they stand for? Is it a conventional thing? Doesnt matter, next question; Berlin Brown http://www.botspiritcompany.com/botlist Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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