How to find biggest item in the array within constant time complexity

public class BiggestnumberInArray {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int arr[] = {1,8,10,40,30,60,50,0,-2}; 
		System.out.println("The biggest Item is : "+
        new BiggestnumberInArray().findBiggestItem(arr));
	}

	public int findBiggestItem(int arr[]) {
		int biggest=0;
		for (int i : arr) {
			
			if(biggest==0) {
				biggest=i;
			}
			if(biggest < i) {
				biggest = i;
			}
		}
		return biggest;
	}
}


Output:-
The biggest Item is : 60