A.java

private static final ObjectMapper OM = new ObjectMapper();

public static String escapeString(Object o) {
    if (o == null) {
        return null;
    }
    try {
        // The string is automatically quoted. Therefore, return a new string that
        // doesn't contain those quotes (since the caller appends quotes themselves).
        val bytes = OM.writeValueAsBytes(o.toString());
        return new String(bytes, 1, bytes.length - 2, StandardCharsets.UTF_8);
    } catch (JsonProcessingException e) {
        return "";
    }
}