nd4j-common/src/main/java/org/nd4j/util/StringUtils.java
public static String[] split(
            String str, char separator) {
        // String.split returns a single empty result for splitting the empty
        // string.
        if (str.isEmpty()) {
            return new String[]{""};
        }
        ArrayList<String> strList = new ArrayList<String>();
        int startIndex = 0;
        int nextIndex = 0;
        while ((nextIndex = str.indexOf(separator, startIndex)) != -1) {
            strList.add(str.substring(startIndex, nextIndex));
            startIndex = nextIndex + 1;
        }
        strList.add(str.substring(startIndex));
        // remove trailing empty split(s)
        int last = strList.size(); // last split
        while (--last>=0 && "".equals(strList.get(last))) {
            strList.remove(last);
        }
        return strList.toArray(new String[strList.size()]);
    }
public static String[] split(
            String str, char separator) {
        // String.split returns a single empty result for splitting the empty
        // string.
        if (str.isEmpty()) {
            return new String[]{""};
        }
        ArrayList<String> strList = new ArrayList<String>();
        int startIndex = 0;
        int nextIndex = 0;
        while ((nextIndex = str.indexOf(separator, startIndex)) != -1) {
            strList.add(str.substring(startIndex, nextIndex));
            startIndex = nextIndex + 1;
        }
        strList.add(str.substring(startIndex));
        // remove trailing empty split(s)
        int last = strList.size(); // last split
        while (--last>=0 && "".equals(strList.get(last))) {
            strList.remove(last);
        }
        return strList.toArray(new String[strList.size()]);
    }
Split a string using the given separator, with no escaping performed.
@param str a string to be split. Note that this may not be null.
@param separator a separator char
@return an array of strings