Parameters and Return Types in Methods

Parameters

The parameters are the inputs that a Java method takes. These are given as an ordered list in parentheses next to the name of the method. We can have any number of parameters.

• If a method does not have any parameters, the parentheses are left empty.

  public static void function()
  {
    // implementation here
  }
  

• Otherwise, for each parameter, we give the type and the name, separated by a comma, in the method’s signature.

  public static void function(type p1, type p2, ..., type pN)
  {
    // implementation here
  }
  

Here, the type of the parameters can be primitive (e.g., int or double) or reference (e.g., a class’s object).

Return type

The return type of a method tells you what kind of value that method returns. For example, a method that calculates the area of a quadrilateral might have a double return type (lines 4-8), whereas a method that concatenates day, month, and year to return a date may have a String return type (lines 11-15).