Re: Virtual function call from constructor

From:
"Mike Schilling" <mscottschilling@hotmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 24 Jun 2007 18:55:29 -0700
Message-ID:
<lgFfi.7102$bP5.3434@newssvr19.news.prodigy.net>
"Eric Sosman" <esosman@acm-dot-org.invalid> wrote in message
news:d76dnVd3HI2Hh-LbnZ2dnUVZ_v2knZ2d@comcast.com...

Mike Schilling wrote:

"Twisted" <twisted0n3@gmail.com> wrote in message
news:1182724872.690108.309670@k79g2000hse.googlegroups.com...

Think of it this way. When the Object constructor is running, the
instance
*is* an Object. It may have some extra space allocated at the end, but
no
one can make any use of it. Now, when the OutputStream constructor is
running, the instance *is* an OutputStream. It may have some extra
space
allocated at the end, but no one can make any use of it. etc. Finally,
when
the PrintStream constructor runs, it *is* a PrintStream.

Except that in Java it's a PrintStream from the outset, and is not a
vanilla Object even when Object's constructor is not finished yet.
(Does Object even have a nontrivial constructor?)


That's presumably a JVM-specific question.


    No; that's the Java language. If Object's constructor
ultimately chained from a PrintStream constructor were to
evaluate `this instanceof PrintStream' the result would be
`true', on every JVM. (Object's constructor has no reason
to do any such thing, but that's another matter.)


The question was "Does Object even have a nontrivial constructor?" That is,
whether its constructor contain any code. As far as I know, that can differ
between implementations.

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