Implementation of standard hashing algorithm in Java

HashString.java

package org.example;

public class Main {

	private static long power(long x, long y) {
		if (y == 0) {
			return 1;
		} else if (y == 1) {
			return x;
		}
		if ((y & 0x1) == 0) {
			return power(x * x, y >> 1);
		} else {
			return x * power(x, y - 1);
		}
	}

	private static long hash(String input) {
		long hash = 0L;
		for (int i = 0; i<input.length(); i++) {
			hash += power(31, input.length() - i - 1) * input.charAt(i);
		}
		return hash % power(2, 32);
	}

	public static void main(String[] args) throws InterruptedException {
		String input = "hello world";
		System.out.println(input.hashCode());
		System.out.println(hash(input));
	}

}