示例 

int[] nums = new int[10];
// fill
Arrays.fill(nums, 666);
System.out.println(Arrays.toString(nums));
// sort
nums = new int[]{1, 3, 5, 7, 9, 2, 4, 6, 8};
Arrays.sort(nums);
System.out.println(Arrays.toString(nums));
// equals
int[] nums2 = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9};
System.out.println(Arrays.equals(nums, nums2));
// binarySerarch
int x = Arrays.binarySearch(nums, 2);
System.out.println(x);