java无法将数组内联赋值给非局部变量

int[] arr1 = {1, 2, 3};
int[] arr2 = new int[arr1.length];
System.arraycopy(arr1, 0, arr2, 0, arr1.length);

int[] arr1 = {1, 2, 3};
int[] arr2 = Arrays.stream(arr1).toArray();

int[] arr1 = {1, 2, 3};
int[] arr2 = arr1.clone();

int[] arr1 = {1, 2, 3};
int[] arr2 = new int[arr1.length];
for (int i = 0; i < arr1.length; i++) {
    arr2[i] = arr1[i];
}