Convert Java Array to Iterable

Question

Integer foo[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };

List<Integer> list = Arrays.asList(foo);
// or
Iterable<Integer> iterable = Arrays.asList(foo);

Though you need to use an Integer array (not an int array) for this to work.

For primitives, you can use guava:

Iterable<Integer> fooBar = Ints.asList(foo);

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>15.0</version>
    <type>jar</type>
</dependency>

For Java8 with lambdas: (Inspired by Jin Kwon's answer)

final int[] arr = { 1, 2, 3 };
final Iterable<Integer> i1 = () -> Arrays.stream(arr).iterator();
final Iterable<Integer> i2 = () -> IntStream.of(arr).iterator();
final Iterable<Integer> i3 = () -> IntStream.of(arr).boxed().iterator();

just my 2 cents:

final int a[] = {1,2,3};

java.lang.Iterable<Integer> aIterable=new Iterable<Integer>() {

    public Iterator<Integer> iterator() {
       return new Iterator<Integer>() {
            private int pos=0;

            public boolean hasNext() {
               return a.length>pos;
            }

            public Integer next() {
               return a[pos++];
            }

            public void remove() {
                throw new UnsupportedOperationException("Cannot remove an element of an array.");
            }
        };
    }
};

With Java 8, you can do this.

final int[] arr = {1, 2, 3};
final PrimitiveIterator.OfInt i1 = Arrays.stream(arr).iterator();
final PrimitiveIterator.OfInt i2 = IntStream.of(arr).iterator();
final Iterator<Integer> i3 = IntStream.of(arr).boxed().iterator();

Guava provides the adapter you want as Int.asList(). There is an equivalent for each primitive type in the associated class, e.g., Booleans for boolean, etc.

int foo[] = {1,2,3,4,5,6,7,8,9,0};
Iterable<Integer> fooBar = Ints.asList(foo);
for(Integer i : fooBar) {
    System.out.println(i);
}

The suggestions above to use Arrays.asList won't work, even if they compile because you get an Iterator<int[]> rather than Iterator<Integer>. What happens is that rather than creating a list backed by your array, you created a 1-element list of arrays, containing your array.

In Java 8 or later, Iterable is a functional interface returns Iterator. So you can do this.

static Iterable<Integer> convert(int[] array) {
    return () -> Arrays.stream(array).iterator();
}

and

int[] array = {1, 2, 3};
Iterable<Integer> iterable = convert(array);
for (int i : iterable)
    System.out.println(i);

output:

1
2
3