在数组中，元素存储的是图元还是对象？

Question

int[] array = new int[10];
for (int i = 0; i < array.length; i++) {
    array[i] = 0;
}

in this example, is the value 0 stored inside the array as a primitive or as an object?

Many thanks

Answer 1

In this case, the value is stored as a primitive. If you changed the type to a primitive's wrapper Integer , the value would go in as an "auto-boxed" Object then. For example, this code would autobox your values:

Integer[] array = new Integer[10];
for (int i = 0; i < array.length; i++) {
    array[i] = 0;
}

Answer 2

In Java, there are both arrays of primitives, and arrays of objects.

int[] is an array of primitives, so 0 is stored as a primitive.

The corresponding array of objects would be of type Integer[] . Storing 0 in such an array would result in it being "auto-boxed" into an Integer object.

It is worth pointing out that Java containers (and any other generic classes) can only work with objects. For example, it is impossible to construct a List of int , only a List of Integer . As I've explained above, this restriction does not apply to arrays.