code: public static String replaceStringInString(final String text, final String searchString, final String replacement) {
          if (stringIsBlank(text) || stringIsBlank(searchString) || replacement == null) {
              return text;
          }
  
          int start = 0;
          int end = text.indexOf(searchString, start);
          if (end == INDEX_NOT_FOUND) {
              return text;
          }
  
          final int replacedLength = searchString.length();
  
          final StringBuilder builder = new StringBuilder();
          while (end != INDEX_NOT_FOUND) {
              builder.append(text.substring(start, end)).append(replacement);
              start = end + replacedLength;
              end = text.indexOf(searchString, start);
          }
          builder.append(text.substring(start));
          return builder.toString();
      }
docs: Replaces all occurrences of a string within a larger string with a replacement string.
  
  @param text
  text to search and replace in, may be {@code null}
  @param searchString
  the String to search for, may be {@code null}
  @param replacement
  the String to replace it with, may be {@code null}
  @return the text with any replacements processed, {@code null} if null String input