Bad char shift

package System;

import java.util.ArrayList;

public class Search {
    private int[] bad_shift; //Jeg finner ikke et bedre navn. Koperte dette fra timen.
    private final int CHAR_MAX = 256;

    public Search() {
        bad_shift = new int[CHAR_MAX];
    }

    public int[] find(char[] needle, char[] haystack){
        ArrayList<Integer> list = new ArrayList<>();
        if (needle.length>haystack.length) return null;
        if (needle.length == 0) return new int[0];

        for (int i = 0; i < bad_shift.length; i++) {
            bad_shift[i] = needle.length;
        }

        int offset = 0, needleScan = 0;
        int maxOffset = haystack.length - needle.length;
        int end = needle.length-1;

        for (int i = 0; i < end; i++) {
            bad_shift[(int)needle[i]] = end - i;
        }

        while(offset < maxOffset){
            //The needleScan start at the end and check backwards until it hits a mismatch. Since _ should allow any kind of symbol
            //then we can simply skip once if we find this char in the current needle char.
            for(needleScan = end; needle[needleScan] == haystack[needleScan+offset] || needle[needleScan] == '_'; needleScan--){
                if(needleScan == 0){ // this will count down for every match until 0. Then we have found the needle.
                    list.add(new Integer(offset));
                    break;
                }
            }
            offset += bad_shift[haystack[offset + end]];
        }

        Integer[] temp = list.toArray(new Integer[list.size()]);
        int[] results = new int[temp.length];
        for (int i = 0; i < results.length; i++) {
            results[i] = temp[i].intValue();
        }
        return results;
    }
}