code: public static boolean isValidJavaEncoding(String javaEncoding) {
          if (javaEncoding != null) {
              int length = javaEncoding.length();
              if (length > 0) {
                  for (int i = 1; i < length; i++) {
                      char c = javaEncoding.charAt(i);
                      if ((c < 'A' || c > 'Z') && (c < 'a' || c > 'z') &&
                          (c < '0' || c > '9') && c != '.' && c != '_' &&
                          c != '-') {
                          return false;
                      }
                  }
                  return true;
              }
          }
          return false;
      }
docs: Returns true if the encoding name is a valid Java encoding.
  This method does not verify that there is a decoder available
  for this encoding, only that the characters are valid for an
  Java encoding name.
  
  @param javaEncoding The Java encoding name.