JEP 186: Collection Literals

Per Bothner per at
Tue Jan 21 12:53:29 PST 2014

On 01/21/2014 11:39 AM, Brian Goetz wrote:
> So, there's been some good discussion regarding the proper scope of
> Collection Literals, so let me summarize what I heard.  I am sensing
> that the center of gravity is roughly behind these points:

I'm good with your summary, though I'd add one note:

> 2.  Having these literals be mutable would be surprising.

I think it depend on the target type - whether it's explicit or implicit.
For example:

ArrayList<String> s1 = {"a", "b" };
List<String> s2 = {"a", "b" };

I think if a concrete type is the target, then that controls
mutability.  If the target is an interface, then we should infer
a "default implementation class" - which should be immutable, at
least for any builtin support.  One way to specify this:

public interface List<T> extends ... {
    public static final Class DEFAULT_CLASS_FOR_LITERAL = 
	--Per Bothner
per at

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