JDK-7140820 : (coll) Add covariant overrides to Collections clone methods
  • Type: Enhancement
  • Component: core-libs
  • Sub-Component: java.util:collections
  • Affected Version: 8
  • Priority: P4
  • Status: Closed
  • Resolution: Won't Fix
  • OS: generic
  • CPU: generic
  • Submitted: 2012-01-30
  • Updated: 2021-05-10
  • Resolved: 2015-01-22
Related Reports
Duplicate :  
JDK-8136748 - clone() of legacy collections should have covariant return types
Relates :  
JDK-4349858 - The List Interface should extends Cloneable to ease list cloning
Relates :  
JDK-4881740 - retrofit collection classes to use generics
Relates :  
JDK-8050953 - Fix raw and unchecked lint warnings in sun.text.normalizer.UnicodeSet
Description
The clone methods on the Cloneable collections just return the type Object, as the clone method inherited from Object does.  More precise information about be returned by adding a covariant override of clone to the Cloneable collections.
Comments
The link to the detailed compatibility discussion leads to a 404. Should probably be: https://mail.openjdk.java.net/pipermail/core-libs-dev/2012-February/009119.html
10-05-2021
But alas, given the potentially bad compatibility impact and the number of potential subclasses of collections types, I'm regrettably closing this bug as "will not fix."
22-01-2015
Detailed compatibility discussion: http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-January/009119.html
06-02-2014
Discussion thread on core-libs-dev: http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-January/009086.html
28-02-2013
EVALUATION A fine idea.
30-01-2012