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Office Hours Transcripts Index

Office Hours:
JavaBeansTM Short Course
August 20, 1997

Moderator (MDR): SPK-jaz

SPK-jaz: Hello and welcome to the office hours for the online JavaBeansTM tutorial. I'm John Zukowski, your friendly neighborhood instructor, with MageLang Institute (authors of the JavaBeans tutorial). I'm here specifically to answer any questions about the online JavaBeans tutorial. However, I'll always try to answer anything else.

sivak1: I have a question about JFC. I know developers can use JFC for free, but how about companies?

SPK-jaz: Speaking from a personal reading of the license, not from a SunTM legal perspective, I don't see anything in the license that says a company can't use it. However, every developer would need to "register" as an evaluator. It is prerelease stuff, so I wouldn't go off and create mission-critical applications yet. Having played with three revisions of it so far, it's been a real pain maintaining working source code. It is really early access stuff--truly, only meant for evaluation activities.

genieyili: Has anybody written a servlet?

SPK-jaz: I've done a little with servlets, although I'm not an expert on it. What's the question?

genieyili: I cannot run the servlet class with Microsoft Internet Information Server 3.0. Do you know what the key config for this is, jaz?

SPK-jaz: I haven't tried them with that specific server. I'm not sure if the current revision supports it.

genieyili: Theoretically, srun.exe invokes the JVM to integrate it to the web server, then you can simply call it by URL. So how do you run your servlet?

SPK-jaz: I run them with the JavaTM Web Server.

genieyili: How do you call the servlet by URL?

SPK-jaz: I've included <servlet> tags in my HTML. I've also done the URL thing. You just need to place the servlets in the right directory, and set up the server properly.

genieyili: So you just use a servlet tag in your HTML page, and it automatically runs? How about srun?

SPK-jaz: I'm not familiar with srun. But the <servlet> tag works for pages that go through a server that understands it.

nancye: This is my first Java application. It is a port of a substantial program from C++, so I have all sorts of questions! For example, I cannot find a built-in linked-list class. Am I missing it?

SPK-jaz: You need to work with something that implements the Enumeration interface. You can keep data in a Vector or Hashtable, and then ask for their elements.

nancye: Thanks, I will look into that. I have another question. I have been using the search engine here on the Sun site to try to find answers. Now that I know about these forums, I will be here also. Any other good online approaches to finding answers quickly?

SPK-jaz: Outside of the Java Developer Connection, there are several searchable resources available. You can visit/search each of them. I maintain a place where you can go to search each at http://java.miningco.com/library/blsearch.htm. It lists about twenty different searchable Java resources.

nancye: Your searchable site is a gold mine. I am going to search it for any porting help I can find.

JoeSam: I've got a tangential question on behalf of someone else.

SPK-jaz: Go for it... ;-)

JoeSam: Hold your nose for a moment. It is regarding the ActiveX bridge. There's a guy who just wants to use an ActiveX control, because it has functionality he needs.

SPK-jaz: What language is the ActiveX control written in?

JoeSam: I guess C++, I'm not sure. It looks like all the bridge stuff is ActiveX to Java. Do you know of a way in Beans, bridge, etc. to run one of those? I understand this is totally nonportable.

SPK-jaz: The bridge is meant to place a Bean component in a COM container, not the other way around.

JoeSam: Yeah, that's the way things looked, but I thought maybe there was another half I was missing.

SPK-jaz: What you would need to do is create a wrapper class that uses native code to communicate with the ActiveX control. IBM has a Migration Assistant to help in the process.

JoeSam: Yeah, Taligent, actually. Depending on how long they get to hang around. This guy wanted to use RTF. I don't think Java, as it currently is, could do much with it fontwise, etc.

SPK-jaz: Look at JTextPane in Swing. It works--cool stuff. It's really easy to work with.

JoeSam: Yeah, for you. I may have mentioned that most of my background is in the IBM midrange, primarily AS/400. IBM, as I'm sure you know, is working on Java in a big way--about 4 times the number of Sun people.

uomini: Does anyone know if JFC includes an HTML-interpreter Bean? Sun said that it would, during JavaOneTM this year.

SPK-jaz: I don't recall seeing one yet. There is the JTextPane class that would allow you to display multifont/images. So, once that is perfected, it should be easy to add the HTML wrapper.

JoeSam: One of the Java Server people talked about including one there. I don't know why. JFC seems the logical place.

uomini: On another note: there are two serious bugs in JDKTM 1.1.3, which were also in 1.1 (I know because I filed a bug report on Dec. 9 for one of them).

SPK-jaz: There were some HTML support classes in an early review of the servlet stuff. Did you file a bug report for the other one since then?

uomini: No, I kept hoping that it would get fixed. The problem involved scrollbars.

SPK-jaz: If they don't know about it, then it can't get fixed. ;-) Of course, for the one you did report... I've never actually determined their order of correcting things.

uomini: Specifically, the size of the scrollbar wasn't set properly, so I can't scroll. Major bummer! My application is over 25,000 lines long, and sometimes it's hard to reproduce a bug in a small chunk of code.

JoeSam: Hey, it's worse now ( 1.1.3 ), scrollbars don't work properly. Do your own sizing based on the object you want to scroll. It's not fun, but it won't (fingers crossed) get broken later.

SPK-jaz: If it can't be reproduced in a small chunk, there is no way to determine who/what is at fault.

uomini: Yes there is: it works fine under JDK 1.0.2. I don't want to rewrite my app with Beans/JFC unless there is a compelling reason to do so. What do you say?

SPK-jaz: The lightweight Beans in Swing will be faster than the AWT Beans, and have more reliable cross-platform behavior.

JoeSam: If it ain't broke don't fix it, unless you're creating lots of AWT objects. Do you agree, jaz?

SPK-jaz: Right now, in Java 1.0, you do not get reliable cross-platform behavior.

JoeSam: Recompile with 1.1.x

SPK-jaz: Recompiling alone won't do it. You have to port to 1.1 event model. However, you are still relying on the peer to deliver the initial event.

uomini: OK, I'll try recompiling, although I wouldn't think the bytecodes have changed.

SPK-jaz: With Swing components, everything stays native to Java.

uomini: Maybe the new event-delivery structure is the source of the resize/scrollbar problems. I'll try converting to Swing (is that JFC?) and see how it flies. I've been away for over three months (vacation), and a lot has happened.

SPK-jaz: If anyone has any last questions about the class, please ask. For general Java questions, bring your code to tomorrow's Code Clinic.

uomini: What is the "online class"?

SPK-jaz: There is an online class on JavaBeans (which these office hours are for). It takes you from the BeanBox, to creating your own Beans with customizers, and what not. The class will be online. You can also download it and run it locally.

uomini: It's exciting to see all the Java-related activity out in the real world.

TomChavez: Wait til next week with JIBE in New York. We'll be focusing on all of the cool work that ISVs are doing. There will be print ads, and stuff on the main web site, links to all of the companies.

uomini: Well, I hope all this somehow translates into increased profits for Sun. I love the direction the stock has taken lately :-)

LDenevi: I want to learn more about JIBE

TomChavez: JIBE info is on our web site, with pointers to the site at Softbank. I don't have the URL handy, but it's the first story on java.sun.com

LDenevi: JIBE, is it just for 3rd party developers to show-off their stuff?

TomChavez: Go to www.javaexpo.sbforums.com (it's in the article about the show).

uomini: Specifically, there will be a lot of IT decision makers at the show (translate: potential customers). So if you've got a product which fits in the enterprise, JIBE might be a good place to exhibit.

TomChavez: It's a trade show for any Java/Internet developers to present. It's focused on the enterprise customer who is looking for solutions to implementing Java in their
business.

It's the place to be to make sales to big biz. Our next big show is Internet World in NY in December, then JavaOneTM. Go to www.mecklermedia.com for more details on that show. Or you can go straight to the events site (events.internet.com). Can you tell I'm browsing as we speak?

SPK-jaz: There is an online class on JavaBeans (which these office hours are for). If no one has any more questions then I'm going to head out, Come back next week, and stop by the Code Clinic (check the schedule). By the way, if you want to report problems with the forum, send email to jdc-webmaster@java.sun.com Thanks for coming and see you next time.

coffeecup



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