JDK-8027284 : 5.1.9: Unchecked conversion for multidimensional arrays
  • Type: Bug
  • Component: specification
  • Sub-Component: language
  • Affected Version: 7
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • Submitted: 2013-10-24
  • Updated: 2014-02-26
  • Resolved: 2013-12-11
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JDK 8
8Fixed
Related Reports
Relates :  
JDK-6508599 - 5.1.9: No unchecked conversion for array types
Description
Unchecked conversion is defined for one-dimensional array types:
List[] -> List<String>[]

But not for multi-dimensional array types:
List[][] -> List<String>[][]

Presumably, this is simply an oversight.

javac (versions 6 through 8) supports both examples.
Comments
Using the []k notation in 5.1.9 addresses the problem.
11-12-2013
I've used the notation "G[]k" (k in superscript) to refer to arrays of arbitrary dimension when referring to unchecked conversion in the Lambda Spec, Chapter 18. (See 18.2.2.)
01-11-2013
6508599 did not intend to limit unchecked conversion of array types to one dimension, but I guess that's how it came out.
25-10-2013