Setting a list of values for a Java ArrayList works:
Integer[] a = {1,2,3,4,5,6,7,8,9};
ArrayList<Integer> possibleValues2 = new ArrayList<Integer>(Arrays.asList(a));
However, the following doesn't work and has the error "Illegal start of type" as well as other. Why not? Since the first line in the first code block is simply assignment, shouldn't it not have an effect?
ArrayList<Integer> possibleValues2 = new ArrayList<Integer>(Arrays.asList({1,2,3,4,5,6,7,8,9}));
You should use either the vararg version of Arrays.asList, e.g.
ArrayList<Integer> possibleValues2 =
new ArrayList<Integer>(Arrays.asList(1,2,3,4,5,6,7,8,9));
or explicitly create an array parameter, e.g.
ArrayList<Integer> possibleValues2 =
new ArrayList<Integer>(Arrays.asList(new Integer[]{1,2,3,4,5,6,7,8,9}));
A strange and little used idiom,
List<Integer> ints = new ArrayList<Integer>() {{add(1); add(2); add(3);}}
This is creating an anonymous class that extends ArrayList (outer brackets), and then implements the instance initializer (inner brackets) and calls List.add() there.
The advantage of this over Arrays.asList() is that it works for any collection type:
Map<String,String> m = new HashMap<>() {{
put("foo", "bar");
put("baz", "buz");
...
}}
new ArrayList<Integer>(Arrays.asList(1,2,3)). It's nice ans sinple, and it leaves the class hierchy untouched
Another option is to use Guava ("Google collections"), which has a Lists.newArrayList(...) method.
Your code would be something like
ArrayList<Integer> possibleValues2 = Lists.newArrayList(1,2,3,4,...);
Arrays.asList() when called with an int[] array
int[] array, Lists.newArrayList(Ints.asList(intArray)) would work though.
int[] array (it's Integer[].) The problem is the braces. Using a different method to create the list will not help. Also the OP is probably a Java newbie and would not benefit from adding another large library to his project.From Java 7 SE docs:
List<Integer> possibleValues2 = Arrays.asList(1,2,3,4,5,6,7,8,9);
