Taxable Interface

Here is Taxable:

• A Taxable item,
  • has a taxRate of 6 percent, which should be a double constant.
  • and a calculateTax() method. which should return a double value.

The Taxable interface looks like this:

interface Taxable
{
  final double  =  ;
  double () ;
}

final means that what follows is a constant, not a variable. Variables are not allowed in interfaces. In fact, the final can be omitted since the compiler will automatically make the identifier a constant. The = value part cannot be omitted.

The method declaration (in the second line) is public by default.