(Maximum element in ArrayList) Write the following method that returns the maximum value in an ArrayList of integers. The method returns null if the list is null or the list size is 0

/*********************************************************************************
* (Maximum element in ArrayList) Write the following method that returns the     *
* maximum value in an ArrayList of integers. The method returns null if the      *
* list is null or the list size is 0.                                            *
*                                                                                *
* public static Integer max(ArrayList<Integer> list)                             *
*                                                                                *
* Write a test program that prompts the user to enter a sequence of numbers      *
* ending with 0, and invokes this method to return the largest number in the     *
* input.                                                                         *
*********************************************************************************/
import java.util.Scanner;
import java.util.ArrayList;

public class Exercise_11_04 {
	// Main method
	public static void main(String[] args) {
		// Create a Scanner
		Scanner input = new Scanner(System.in);

		// Create an ArrayList
		ArrayList<Integer> list = new ArrayList<Integer>();

		// Prompt the user to enter a sequence of numbers ending with 0
		System.out.print("Enter a sequence of numbers ending wih 0: ");
		Integer number = input.nextInt();
		while (number.intValue() != 0) {
			list.add(number);
			number = input.nextInt();
		}

		// Display the largest number in the input 
		System.out.println("The largest number in the input is " + max(list));
	}

	/** Return the maximum value in an ArrayList of integers */
	public static Integer max(ArrayList<Integer> list) {
		if (list.size() == 0)
			return null;

		Integer max = list.get(0);
		for (int i = 0; i < list.size(); i++) {
			if (list.get(i) > max)
				max = list.get(i);
		}
		return max;
	}
}