Convert String to Integer and 2D Integer Array

StringTo2DArray.java

public static class StringTo2DArray implements Function<String, int[][]> {

    @Override
    public int[][] apply(String s) {

        String trimmed = s.trim();
        String arraysString = s.substring(1, trimmed.length() - 1);

        String[] arrays = arraysString.replaceAll("]\\s*,\\s*\\[", "]\n[")
                .split("\n");
        StringToArray mapper = new StringToArray();
        return Arrays.stream(arrays)
                .map(mapper)
                .toArray(int[][]::new);
    }
}

public static class StringToArray implements Function<String, int[]> {

    @Override
    public int[] apply(String s) {
        String trimmed = s.trim();
        return Arrays.stream(trimmed.substring(1, trimmed.length() - 1)
                .split(","))
                .map(String::trim)
                .mapToInt(Integer::parseInt)
                .toArray();
    }
}