Sometimes conversion of primitive types to boxed types is necessary.
To convert the array, it’s possible to use streams (in Java 8 and above):
int[] primitiveArray = {1, 2, 3, 4};
Integer[] boxedArray =
Arrays.stream(primitiveArray).boxed().toArray(Integer[]::new);With lower versions it can be by iterating the primitive array and explicitly copying it to the boxed array:
int[] primitiveArray = {1, 2, 3, 4};
Integer[] boxedArray = new Integer[primitiveArray.length];
for (int i = 0; i < primitiveArray.length; ++i) {
boxedArray[i] = primitiveArray[i]; // Each element is autoboxed here
}Similarly, a boxed array can be converted to an array of its primitive counterpart:
Integer[] boxedArray = {1, 2, 3, 4};
int[] primitiveArray =
Arrays.stream(boxedArray).mapToInt(Integer::intValue).toArray();Integer[] boxedArray = {1, 2, 3, 4};
int[] primitiveArray = new int[boxedArray.length];
for (int i = 0; i < boxedArray.length; ++i) {
primitiveArray[i] = boxedArray[i]; // Each element is outboxed here
}