public static void main(String[] args) {

    String str = "ABCD";

    char[] chars =  str.toCharArray();

    char[] charElements = new char[chars.length];

    int charLen = chars.length-1;

    int charInitialIndex = 0;

    RecursiveArrayCopyAlgorithm testSearch = new RecursiveArrayCopyAlgorithm();

    char[] charObjs = testSearch.callLinear(charLen, charInitialIndex, chars, charElements);

    for (int i = 0; i < charObjs.length; i++) {
        System.out.println(charObjs[i]);
    }

}

private char[] callLinear(int charLen, int index,char[] ch, char[] charElements) {
    int index1 = charLen;

    if(index1 < 0) {
        return charElements;
    }

    if(index1 >= 0) {
        charElements[index] = ch[index1];
    }

    return callLinear(charLen-1, index+1, ch, charElements);
}