public static String replaceStrings(String properties, String property, String value) {
    StringBuilder sb = new StringBuilder();
    int start = 0;
    int index = properties.indexOf(property);
    while (index != -1) {
      sb.append(properties, start, index);
      sb.append(value);

      start = index + property.length();
      index = properties.indexOf(property, start);
    }
    sb.append(properties.substring(start));
    return sb.toString();
  }
replaces all occurrences of a given string in the properties argument with the given value
geode-membership/src/main/java/org/apache/geode/distributed/internal/membership/gms/GMSUtil.java