4. Valid Java Identifiers

• The rules for naming an identifier:

  • Start each identifier with a letter, underscore, or dollar sign. Use letters, dollar signs, underscores, or digits for subsequent characters.

  • Use up to 255 characters.

  • Don't use Java keywords.

  InvoiceApp          $orderTotal     i
  Invoice             _orderTotal     x
  InvoiceApp2         input_string    TITLE
  subtotal            _get_total      MONTHS_PER_YEAR
  discountPercent     $_64_Valid