Check if sum of number exist in the array

/**
 *
 */
package com.cfed.tutorials;

import java.util.HashSet;
import java.util.Set;

/**
 * @author Apple
 *
 */
public class CheckingIfSumExist {

private boolean sumExistOrNotSorted(int[] array, int sum) {
int len = 0;
if ((len = array.length) <= 0)
return false;

int low = 0;
int high = len;

while (low < high) {

}

return false;

}

private boolean sumExistOrNot(int[] array, int sum) {
int len;
if ((len = array.length) <= 0)
return false;

Set<Integer> complimentList = new HashSet<>();

for (int i = 0; i < len; i++) {

int value = array[i];

if (complimentList.contains(value))
return true;
else {
int complimentValue = sum - value;
complimentList.add(complimentValue);
}
}

return false;

}

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub

CheckingIfSumExist c = new CheckingIfSumExist();

int[] array = { 1, 3, 9, 4 };
System.out.println(c.sumExistOrNot(array, 8));

}

}