public static String unquote(String s) {
    if (s.startsWith("[[") && s.endsWith("]]"))
      return s.substring(2, s.length()-2);
    else if (s.startsWith("\"") && s.endsWith("\"") && s.length() > 1) {
      String st = s.substring(1, s.length()-1);
      StringBuilder sb = new StringBuilder(st.length());
  
      for (int i = 0; i < st.length(); i++) {
        char ch = st.charAt(i);
        if (ch == '\\') {
          char nextChar = (i == st.length() - 1) ? '\\' : st
                  .charAt(i + 1);
          // Octal escape?
          if (nextChar >= '0' && nextChar <= '7') {
              String code = "" + nextChar;
              i++;
              if ((i < st.length() - 1) && st.charAt(i + 1) >= '0'
                      && st.charAt(i + 1) <= '7') {
                  code += st.charAt(i + 1);
                  i++;
                  if ((i < st.length() - 1) && st.charAt(i + 1) >= '0'
                          && st.charAt(i + 1) <= '7') {
                      code += st.charAt(i + 1);
                      i++;
                  }
              }
              sb.append((char) Integer.parseInt(code, 8));
              continue;
          }
          switch (nextChar) {
          case '\\':
              ch = '\\';
              break;
          case 'b':
              ch = '\b';
              break;
          case 'f':
              ch = '\f';
              break;
          case 'n':
              ch = '\n';
              break;
          case 'r':
              ch = '\r';
              break;
          case 't':
              ch = '\t';
              break;
          case '\"':
              ch = '\"';
              break;
          case '\'':
              ch = '\'';
              break;
          // Hex Unicode: u????
          case 'u':
              if (i >= st.length() - 5) {
                  ch = 'u';
                  break;
              }
              int code = Integer.parseInt(
                      "" + st.charAt(i + 2) + st.charAt(i + 3)
                              + st.charAt(i + 4) + st.charAt(i + 5), 16);
              sb.append(Character.toChars(code));
              i += 5;
              continue;
          }
          i++;
        }
        sb.append(ch);
      }
      return sb.toString();      
    } else
      return s; // return original
  }

Began life as a copy of #2000471