Java functions


In Java, functions are referred to as methods. Methods are blocks of code that perform a specific task and can be called by their name to execute that task. Here’s an overview of how methods work in Java:

Defining a Method:

A method is defined within a class and consists of a method signature and a method body.

accessModifier returnType methodName(parameterList) {
    // Method body
    // Code to perform the task
    // ...
    return returnValue; // Optional return statement
  • accessModifier: Specifies the visibility of the method (e.g., public, private, protected, or package-private).
  • returnType: Specifies the data type of the value returned by the method. Use void if the method doesn’t return anything.
  • methodName: The name of the method.
  • parameterList: The list of input parameters the method accepts (can be empty).
  • returnValue: The value that the method returns (if the returnType is not void).

Calling a Method:

To use a method, you call it by its name and provide any required arguments (parameters) based on its parameter list.

returnType result = methodName(argument1, argument2, ...);


Here’s a simple example of a method that calculates the sum of two numbers:

public class MathUtils {
    public static int add(int a, int b) {
        return a + b;

    public static void main(String[] args) {
        int x = 5;
        int y = 7;
        int sum = add(x, y); // Calling the method
        System.out.println("Sum: " + sum);

In this example, the add method takes two integer parameters and returns their sum. The main method demonstrates how to call the add method and display the result.

Types of Methods:

  1. Static Methods: Defined using the static keyword. They belong to the class and can be called using the class name (e.g., MathUtils.add()).
  2. Instance Methods: Associated with instances (objects) of the class. They are called on instances of the class.
  3. Methods with Return Values: Methods that return a value. The return type should be specified in the method signature.
  4. Methods without Return Values: Methods with a void return type. They perform actions without returning a value.
  5. Method Overloading: Defining multiple methods with the same name but different parameter lists.
  6. Method Overriding: Inheritance allows a subclass to provide a specific implementation for a method that’s already defined in its superclass.
  7. Constructors: Special methods used for object initialization. They have the same name as the class and don’t have a return type.

Java’s methods play a crucial role in structuring code and enabling code reuse. Understanding how to define and use methods is fundamental to Java programming.

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