code: public static boolean isBigInteger(CharSequence self) {
          try {
              new BigInteger(self.toString().trim());
              return true;
          } catch (NumberFormatException nfe) {
              return false;
          }
      }
docs: Determine if a CharSequence can be parsed as a BigInteger.
  
  @param self a CharSequence
  @return true if the CharSequence can be parsed
  @see #isBigInteger(String)
  @since 1.8.2