Frequently asked questions, or "the human Google"

June 28, 2007

I really like the JDeveloper Forum on OTN. I have a little desktop widget that uses RSS to show the latest posts as they come in. I read the forum almost like a Blog – it’s always interesting, informative, and helpful to see what issues people are grappling with; lots of times, I get new ideas to try by reading posts there. I also try to answer as many of the questions that come up as I can. Why? The forum was helpful to me starting out, and, personally, I’d like to see others be successful with JDeveloper and the marketplace for JDeveloper to grow – purely for selfish reasons. I’m a consultant, and the more potential customers use JDeveloper and Oracle stuff, the more potential customers for me and the company I work for.

As I read the posts, there are some that just come up over and over and over and over. Lots of times, I’ll answer the questions by doing a quick search on the forum and posting the link (hence “the human Google”). So I thought I’d compile a list of questions and answers here, sort of an unofficial FAQ. For what it’s worth, I mostly use ADF Business Components and ADF Faces – not much of an EJB/Swing guy at the moment, so don’t expect to see Swing/EJB questions.

By the way, if there’s a better answer somewhere or something that should be added, let me know and I’ll update the list – just post a comment to this entry.

Some of the questions/answers are a bit tongue-in-cheek 😉


Question: I’d like to create a page to frobdigate the whigginator. It’s urgent so please help me!

Answer: Would you now? Honestly, there are a fair number of questions on the forum that are about this comprehensible. If you want a good answer, be sure to provide enough information so that the readers at least know what you’re talking about.


Question: When will version xyz of JDeveloper be available?

Answer: When it’s ready. I’ve been guilty of asking this question a few times myself.


Question: How do I convert among java.util.Date and oracle.jbo.domain.Date and java.sql.Date

Answer: Here’s a good post that gives a few examples.


Question: How can I create two drop-down list boxes (af:selectOneChoice) such that when I pick a value from the first one, it changes the values in the second one – for example, when I pick the State from the first, the second one should contain a list of cities in that state?

Answer: Frank Nimphius of Oracle has written about this.


Question: I want to add security to my Faces application where I can validate the username and password against a database table. How do I do that?

Answer: Here’s one way.


Question: blah blah blah OAF blah blah Oracle Applications Framework blah blah OA Framework?

Answer: Try the OA Framework forum on OTN.


Question: I want to have a gap-less sequence number as the key for my table, how

Answer: No, you don’t.


Question: but I wasn’t finished with my question yet.

Answer: Yes you were.


Question: OK, I understand I should use a database sequence. Why is the number negative/how do I use the sequence?

Answer: Have a read of the ADF Developer’s Guide for Forms/4GL Developers, section 6.6.3.8 for starters. Then, read the rest of that document 😉


Question: How can I display images that are stored in a blob in the database?

Answer: Read this post


Question: How can I use a drop-down list (af:selectOneChoice) inside of an editable table (af:table)?

Answer: Steve Muench of Oracle did a nice screencast showing how to do that.


Question: How can I call a stored procedure from my application module code? I don’t want to open a new database connection

Answer: Check out this post.


Question: I am trying to connect to my Oracle XE database and am getting errors. What do I need to do?

Answer: The Oracle XE connection information is localhost:1521:XE. Most likely, you forgot to change the SID from “ORCL” to “XE” when you set up the connection.


Question: How do I get the selected label of an af:selectOneChoice? Every time I try, I just get a number

Answer: Frank Nimphius to the rescue again.


Question: How do I highlight the selected row in an af:table?

Answer: Check out this post for a couple of answers.


Who likes JDeveloper and who pooh-poohs?

June 5, 2007

Jan Vervecken started a recent thread on the OTN JDeveloper Forum entitled, “The forgotten Java IDE?” It’s quickly garnered a lot of replies (57 at the current count!). It’s lead me to do some thinking and some researching around the Web.

To paraphrase both Blondie aka “the man with no name” (Clint Eastwood) and Tuco (Eli Wallach) as they were wont to say in my all-time favorite movie, “There are two types of people in the world my friend, those who like JDeveloper, and those who pooh-pooh it.” Well, the world is more complex than that, but it seems to be the case that a given person either loves JDeveloper, or thinks it’s completely useless and irrelevant. Can both types of people be talking about the same thing?

In my experience on the OTN forums, at Java One, and from reading blogs and other Internet posts, I’ve been able to create some stereotypes of the two types of people, and gain some insight into the “why” of the stereotypes.

People who like JDeveloper tend to:

  • Already be Oracle customers
  • Have experience with 4GL languages, especially Oracle Forms
  • Use Oracle’s Application Development Framework (ADF)
  • Like the integrated SOA development tools in JDeveloper

People who pooh-pooh JDeveloper tend to:

  • Think of themselves as “hard-core” java programmers or “java gurus”
  • Dislike anything “proprietary,” and thus tend to discount ADF
  • Really like open source, “free” things (although, as a sidebar, my friend always used to say, “if it’s free, I can’t afford it”)

People who have traditionally used Oracle’s (quite good) 4GL tools like Oracle Forms tend to be able to jump right in to ADF, with some training of course, and work in JDeveloper in a familiar paradigm. For them, learning Java/J2EE in the context of doing a JDeveloper/ADF project, tends to be, “teach me the syntax” and, “learn the ADF framework.” All of the J2EE complexity is hidden under the covers of the ADF framework for these folks.

The hard-core java guys, on the other hand, want to fiddle with every bit and byte. Now, in my opinion, JDeveloper can do this just as well, if not better, than the other IDE’s out there (Eclipse, Netbeans, IntelliJ, etc); however, most of these folks already have an established IDE preference, and changing IDE’s is something that requires a conscious effort and reason to change. Thus, even though I really like JDeveloper, and think it’s a world-class IDE, and would like more people to use it (selfish reasons, I guess – I want to ensure that Oracle will always be putting lots of effort into new releases), I would say to this group of people, “keep using whatever you are using.” If you want a nice productive database development environment, or a nice BPEL development environment, come on over and take a look. Heck, I’d be willing to bet that most of the hard-core guys, if they would be willing to take an honest look at ADF, would find that there are some good things there for them.

As to which type of person am I… I’ve got some characteristics of both. I’ve done some Oracle Forms (mostly Forms 2.3 and Forms 3.0!) programming in my life. I actually got my start doing more hard-core C/C++ programming and did “hard-core” java before I got into ADF; so I guess I don’t fit the stereotypes I’ve laid out here.

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