list literal gotcha and suggestion

Tomas Salfischberger t.salfischberger at
Wed Oct 7 13:19:06 PDT 2009

Reinier Zwitserloot wrote:
> The major point you're missing is the proposal to make list literals 
> implement a to-be-named concrete implementation of java.util.List that 
> has a few useful utility methods, including at least "toSet()". The 
> reason being that:
> {1, 2, 3}.toSet();
> is a lot nicer than:
> Collections.unmodifiableSet(HashSet.of({1, 2, 3}));

Good point, I probably skipped over it somewhere.

> There was some discussion about a tiny detail - should we have of() 
> methods that take varargs, should we have of() methods that takes a 
> Collection (which you could then make with the list literal syntax), 
> or should we just stick with the already existing copy constructors?

We would have to think about the possible use-cases we want to support:

- Immutable List literal
- Mutable LinkedList, HashSet etc
- Immutable LinkedList, HashSet etc

Possibly other combinations?

> Then there's another tiny detail: Should these methods be called 'of', 
> or 'newList'? If you're *NOT* using static imports, then 'of' is much 
> nicer, but if you want to statically import these pseudo-constructors, 
> 'of' is useless.

The 'newList' method would still cause static import conflicts with 
different List implementations, it would have to be' newLinkedList' 
which is just as much characters as 'LinkedList.of'.

Thinking about tool-support I would pick the of() variant, typing 
"LinkedL [ctrl+space] .of" would be enough in most current IDEs to get 
both the import of LinkedList and the statement. The static import 
version would as far as I know require you to manually type the static 
import before using the newLinkedList() method.


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