core/src/main/java/com/google/cloud/sql/core/CoreSocketFactory.java
private static List<String> listIpTypes(String cloudSqlIpTypes) {
    String[] rawTypes = cloudSqlIpTypes.split(",");
    ArrayList<String> result = new ArrayList<>(rawTypes.length);
    for (int i = 0; i < rawTypes.length; i++) {
      if (rawTypes[i].trim().equalsIgnoreCase("PUBLIC")) {
        result.add(i, "PRIMARY");
      } else {
        result.add(i, rawTypes[i].trim().toUpperCase());
      }
    }
    return result;
  }
private static List<String> listIpTypes(String cloudSqlIpTypes) {
    String[] rawTypes = cloudSqlIpTypes.split(",");
    ArrayList<String> result = new ArrayList<>(rawTypes.length);
    for (int i = 0; i < rawTypes.length; i++) {
      if (rawTypes[i].trim().equalsIgnoreCase("PUBLIC")) {
        result.add(i, "PRIMARY");
      } else {
        result.add(i, rawTypes[i].trim().toUpperCase());
      }
    }
    return result;
  }
Converts the string property of IP types to a list by splitting by commas, and upper-casing.