Parameters and Return Types in Methods

In this lesson, we take a closer look at the parameters and return types of methods in Java.

We'll cover the following

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).

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