Re: Java Bean Question

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Tue, 09 Oct 2007 09:24:08 -0400
Message-ID:
<nuSdnQHQFs5lHZbanZ2dnUVZ_vKunZ2d@comcast.com>
Chris ( Val ) wrote:

Point taken, but that's what I have read. Just to clarify, does
that myth also apply to enterprise java beans?


Enterprise JavaBeans are a completely different animal.

Lew wrote:

There is absolutely no mention in the specification of a pattern for the
constructor, not even that there must be a default constructor, much less that
it be specific. In fact, aBeanis not even limited to a single class.


Again, it's just what I have read in some tutorials, possibly
even on Sun's own site.


Citations? I take my information from the JavaBeans specification document,
which one might take to be authoritative. Did you read it?

The spec recommends instantiation through a call to Beans.instantiate().


Just out of interest, where would you make that call? (servlet, JSP,
etc...)


Anywhere you instantiate a Bean. I admit I've never followed that
recommendation, but then I haven't been using the full power of the JavaBeans
framework.

But if I supply my own user defined (overloaded) constructor that
takes arguments, doesn't the side effect of that cause the compiler
or JVM to *not* provide a default constructor anymore? thus it has
to be explicitly defined? or is it still not a requirement that it
be present at all?


Did you notice upthread that I said:

It only needs to be explicit if there is a non-default constructor
or if it does significant construction work, not usual for JSP beans.

?

This is the usual rule for default constructors.

--
Lew

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