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Java Forum / First Aid / April 2008Question about the package directive
I was reading a Java book tonight and it was talking about the "package" directive. I haven't seen it used anywhere. Did it die with one of the more recent versions or is it just obsolete but still available?  Signature* I am the walrus. * * RLU 451587 * * Running Vista Ultimate SP1 and Ubuntu Gutsy Gibbon * * Sea creatures unite and take back usenet http://improve-usenet.org/ * > I was reading a Java book tonight and it was talking about the > "package" directive. I haven't seen it used anywhere. Did it die > with one of the more recent versions or is it just obsolete but still > available? <http://java.sun.com/javase/6/docs/api/overview-summary.html> See all those things on the left hand side? Those are packages. Why the heck would you think "package" isn't being used? It's used everywhere. >> I was reading a Java book tonight and it was talking about the >> "package" directive. I haven't seen it used anywhere. Did it die [quoted text clipped - 7 lines] > Why the heck would you think "package" isn't being used? It's used > everywhere. 'package' is one of the most fundamental keywords in the Java language. Organization of classes into packages is at the heart of how Java organizes libraries. SignatureLew >> I was reading a Java book tonight and it was talking about the >> "package" directive. I haven't seen it used anywhere. Did it die [quoted text clipped - 7 lines] > Why the heck would you think "package" isn't being used? It's used > everywhere. I was thinking about how stupid this question sounded last night after I went to bed. Of course "package" is still used, it's just that the IDE's I use (i.e. Eclipse and Netbeans) tend to insert it automatically for me, it doesn't make it in my view. Sorry man...my bad. Signature* I am the walrus. * * RLU 451587 * * Running Vista Ultimate SP1 and Ubuntu Gutsy Gibbon * * Sea creatures unite and take back usenet http://improve-usenet.org/ * > I was thinking about how stupid this question sounded last night after > I went to bed. Of course "package" is still used, it's just that > the IDE's I use (i.e. Eclipse and Netbeans) tend to insert it > automatically for me, it doesn't make it in my view. > > Sorry man...my bad. No worries. I think we've all made at least one post here that we should have thought about a bit more. I've made at least a couple whoopers myself. So you're in the same club now. Grab a chair, kick off your shoes, grab a beer. We're all human and we make mistakes. (Well, except I think that robot spammer guys isn't human. I hate him.) >> I was thinking about how stupid this question sounded last night after >> I went to bed. Of course "package" is still used, it's just that [quoted text clipped - 9 lines] > > (Well, except I think that robot spammer guys isn't human. I hate him.) Me thinks that my confuddling was compounded by the fact that the book I was reading was written in the 1990's so that's why I figured what I dun figured. We now return you to your regularly scheduled feeding at the zoo. Signature* I am the walrus. * * RLU 451587 * * Running Vista Ultimate SP1 and Ubuntu Gutsy Gibbon * * Sea creatures unite and take back usenet http://improve-usenet.org/ * > Me thinks that my confuddling was compounded by the fact that the book > I was reading was written in the 1990's so that's why I figured what I > dun figured. Ah, well definitely get a newer book. Java has evolved a lot. Sun's online tutorials are good. There's web site, www.javapassion.com which is excellent. I recommend the latest edition of O'Reilly's Learning Java. Excellent beginning book. >> Me thinks that my confuddling was compounded by the fact that the book >> I was reading was written in the 1990's so that's why I figured what I [quoted text clipped - 5 lines] > which is excellent. I recommend the latest edition of O'Reilly's > Learning Java. Excellent beginning book. I have most of the more popular books, including the GOF book and Joshua Bloch's excellent book. But I like to vary my reading from time to time, trying to see how each author(s) approaches the subject of learning Java. So far, Head First Java along with the aforementioned Sun tutorial has proven to be the best for me. Signature* I am the walrus. * * RLU 451587 * * Running Vista Ultimate SP1 and Ubuntu Gutsy Gibbon * * Sea creatures unite and take back usenet http://improve-usenet.org/ * On 21 Apr 2008 23:53:03 GMT, I_Am_The_Walrus <I_Am_The_Walrus@will_f_uup.invalid> wrote, quoted or indirectly quoted someone who said : >I have most of the more popular books, including the GOF book and Joshua Bloch's >excellent book. But I like to vary my reading from time to time, >trying to see how each author(s) approaches the subject of learning >Java. So far, Head First Java along with the aforementioned Sun >tutorial has proven to be the best for me. I have heard several other people ethusiastically recommend that series. Ideally you skim the book before purchasing to make sure it has examples that interest you, and are complete. The book should have the Goldilocks property of difficulty. Picking one too easy or too hard FOR YOU is a waste of money. I have seen so many programmers with shelves of expensive books that look completely unread. An author like Peter van der Linden helps keep you entertained -- a spoonful of whimsy to help the medicine go down. A good measure of the value of a book would be how wrinkled the spine is. Check in a friend's house to see which ones they are. There is now so much good material available free on the net, I have much less reliance on textbooks. I think however, you need at least one decent text to get you started to make sure ALL the basics are covered. SignatureRoedy Green Canadian Mind Products The Java Glossary http://mindprod.com ... > Ideally you skim the book before purchasing to make sure it has > examples that interest you, and are complete. The book should have > the Goldilocks property of difficulty. Picking one too easy or too > hard FOR YOU is a waste of money. ... I do two checks when picking a book for self-education: 1. Read some pages near the start of the book. Reject, at least temporarily, if I don't understand them. I may reconsider after reading a more basic book on the same subject. 2. Dip into later chapters. Reject if they only cover material I already understand. The idea is that my knowledge of the subject should increase in the process of reading the book. Patricia >Java. So far, Head First Java along with the aforementioned Sun >tutorial has proven to be the best for me. I have just looked at a single box on a page of »Head First Java«, which seems to contain significant errors. It claims »Statements end in a semicolon ;« and »A while loop runs everything within its block« in chapter 1 in »Bullet Points« near »Example of a while loop«. > It claims »Statements end in a semicolon ;« and > »A while loop runs everything within its block« > in chapter 1 in »Bullet Points« near »Example of a while loop«. Consider the audience. That is perfectly adequate for a beginning book. You can't explain everything all at once (unless you are writing in German). SignatureRoedy Green Canadian Mind Products The Java Glossary http://mindprod.com >> It claims »Statements end in a semicolon ;« and >> »A while loop runs everything within its block« [quoted text clipped - 5 lines] > You can't explain everything all at once (unless you are writing in > German). So they have to lie? All they had to do was pop the word "usually" in there. SignatureLew >>It claims »Statements end in a semicolon ;« and >>»A while loop runs everything within its block« >>in chapter 1 in »Bullet Points« near »Example of a while loop«. >Consider the audience. That is perfectly adequate for a >beginning book. >You can't explain everything all at once Using correct assertions here isn't more difficult: »Simple statements end in a semicolon. The block is a compound statement. A while loop might execute its statement several times.« The while loop already is a more complex statement. If the audience consists of absolute beginners in programming, it might appear too early in the book. In my classes, I take some time to introduce simple statements (expression statements) and blocks and then do several exercises related to them, so that everyone gets a firm grip of these concepts. So there is no need to make false claims. I even discuss the false belief that »all statements end in a semicolon« in an exercise, where the pupils are asked to review this statement. I often do not treat loops at all, or only when asked about them. For the audience I encounter when I am giving adult evening classes about Java, this book already is too fast and thus too difficult. On 20 Apr 2008 00:16:35 GMT, I_Am_The_Walrus <I_Am_The_Walrus@will_f_uup.invalid> wrote, quoted or indirectly quoted someone who said : >I was reading a Java book tonight and it was talking about the >"package" directive. I haven't seen it used anywhere. Did it die >with one of the more recent versions or is it just obsolete but still >available? see http://mindprod.com/jgloss/package.html SignatureRoedy Green Canadian Mind Products The Java Glossary http://mindprod.com On 20 Apr 2008 00:16:35 GMT, I_Am_The_Walrus <I_Am_The_Walrus@will_f_uup.invalid> wrote, quoted or indirectly quoted someone who said : >I was reading a Java book tonight and it was talking about the >"package" directive. I haven't seen it used anywhere. Did it die >with one of the more recent versions or is it just obsolete but still >available? In toy programs, the class is often not assigned a package. That is why you may have seen import (of packages) but not the package keyword itself. Look at any of Sun's code in the JDK. They will nearly always be assigned to packages to help organise the code. look in src.zip SignatureRoedy Green Canadian Mind Products The Java Glossary http://mindprod.com On 4月20日, 上午8时16分, I_Am_The_Walrus > I was reading a Java book tonight and it was talking about the > "package" directive. I haven't seen it used anywhere. Did it die [quoted text clipped - 6 lines] > * Running Vista Ultimate SP1 and Ubuntu Gutsy Gibbon * > * Sea creatures unite and take back usenethttp://improve-usenet.org/* learn java is mainly to lerarn how to use package.the more you learned,the more important the package is. you will fell so soon >I was reading a Java book tonight and it was talking about the >"package" directive. I haven't seen it used anywhere. Did it die >with one of the more recent versions or is it just obsolete but still >available? The package directive appears at the start of most real world Java source files, it indicates which package each source file belongs to. When you are just starting Java you will see it rarely because the small example programs in the books do not usually bother - each small program concentrates on just one aspect of the language to make the example easier to understand. The package directive is the other side of the import statement. When you say "import java.util" that implies that somewhere there is a group of source files that start "package java.util". The import statement will import all the classes in the files that are marked for that package, i.e. all those files that start "package java.util". It is far from obsolete and is very important when organising a large project. HTH rossum > I was reading a Java book tonight and it was talking about the > "package" directive. I haven't seen it used anywhere. Did it die > with one of the more recent versions or is it just obsolete but still > available? Sample programs normally exist in their own tiny little worlds, where using the package statement only creates clutter. Real programs use packages. SignatureJohn W. Kennedy "The blind rulers of Logres Nourished the land on a fallacy of rational virtue." -- Charles Williams. "Taliessin through Logres: Prelude" >> I was reading a Java book tonight and it was talking about the >> "package" directive. I haven't seen it used anywhere. Did it die [quoted text clipped - 4 lines] > using the package statement only creates clutter. Real programs use > packages. In fact, there are certain things that cannot be done if you stay within the default (i.e., unnamed) package. The JLS itself admonishes: > For small programs and casual development, a package can be unnamed (§7.4.2) > or have a simple name, but if code is to be widely distributed, unique package > names should be chosen (§7.7). <http://java.sun.com/docs/books/jls/third_edition/html/packages.html> and > Unnamed packages are provided by the Java platform principally for convenience > when developing small or temporary applications or when just beginning > development. <http://java.sun.com/docs/books/jls/third_edition/html/packages.html#7.4.2> SignatureLew 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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