Re: arrays and cloning, where is it described?

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 06 Mar 2008 03:16:04 -0500
Message-ID:
<3cidnYmBK5zZNVLanZ2dnUVZ_hGdnZ2d@comcast.com>
Andreas Leitgeb wrote:

The JLS has some strange wording, such as "can be assigned to
variables of types Object, Cloneable, Serializable", instead
of saying that an array *was* all these.


Actually, the JLS does say that an array is all these, in ss. 4.10.3
<http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.10.3>
and in 10.7
<http://java.sun.com/docs/books/jls/third_edition/html/arrays.html#10.7>

Every array implements the interfaces Cloneable and java.io.Serializable.

and 10.8

The direct superclass of an array type is Object.
Every array type implements the interfaces Cloneable and java.io.Serializable.


The combination of Cloneable and Serializable is somewhat rare outside arrays,
because Cloneable is rare. The combination is implemented by various
java.util classes: ArrayList, Calendar, Date, HashMap, HashSet.

Also in java.sql: Date, Time, Timestamp, by dint of subclassing java.util.Date.

There are a number of additional references in the JLS to the relationship
between Cloneable & Serializable and arrays such as ss. 5.1.6 (Narrowing
Reference Conversion), 5.5 (Casting Conversion), 10 (Arrays), and 5.2
(Assignment Conversion), from whence your paraphrase seems to come.

<http://java.sun.com/docs/books/jls/third_edition/html/conversions.html#5.2>

An array can be assigned only to a variable of a compatible array type,
or to a variable of type Object, Cloneable or java.io.Serializable.


That quote makes sense there because it has to do with assignment conversion.

It is also clearly not instead of saying that an array is "all these" but in
addition to several such mentions.

--
Lew

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