Re: this reference in Java constructors

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 28 Oct 2009 23:14:38 -0400
Message-ID:
<hcb1av$dre$1@news.albasani.net>
Eric Sosman wrote:

It's fairly easy to get an arbitrary
amount of code executed *before* the superclass' constructor
runs, as in

    class Counterexample extends HasBoolConstructor {
        Counterexample() {
            super(boolMethod());
        }

        private bool boolMethod() {
            // Twelve SQL queries,
            // Eleven XML parses,
            // Ten external programs,
            // Nine RMI calls,
            // Eight LDAP queries,
            // Seven serializations,
            // Six caught exceptions,
            // Five di-a-logs!
            // Four URLs,
            // Three GC's,
            // Two JAR downloads, and
            return pearTree.add("Partridge");
        }

        private static final HashSet<String> pearTree =
            new HashSet<String>();
    }


In addition to the obvious dangers here that you've already discussed, the
instance-level access to a static structure is problematic. This is a
well-crafted example of code idioms to avoid.

--
Lew

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