This document explains methods in Java, defining them as blocks of code designed to perform specific tasks and process data. It outlines the general structure of methods, types based on return values and arguments, and how methods can be called from classes or objects. Examples illustrate various method types and the necessary components for calling methods effectively.

1. Methods/Functions in Java
• A method is a block of code that is written to perform a specific task.
• A method is like someone you hire to do something for you.
• Java Programs are divided into Data and Methods.
• Methods are used to process data.
• A method is also called as a function/process/procedure/routine

2. General Structure of Methods in Java
Access_Specifier Return_Type method_name(Arguments/Inputs)
{
//Processing
}
1.Access_Specifier : Controls the Access to the method.
2.Return_Type : Determines the type of the value being returned by the
method
3.Method_Name : A name given to a method.
4.Arguments : Inputs passed to a method

3. Example of a Method
public int addTwoNumbers(int a, int b)
{
int sum = a+b;
return sum;
}

4. Types of Methods
• Java Methods are classified into four different types based on:
• 1. Return Type
• 2. Arguments or Data being passed.

5. Type 1. Return Type With Arguments
public double run(double a)
{
return a*3.4;
}

6. Type 2. Return Type With No Arguments
public int move()
{
return 300;
}

7. Type 3. No Return Type With Arguments
public void fight(int z, int w)
{
System.out.println(z*w);
}

8. Type 4. No Return Type With No Arguments
public void useless()
{
System.out.println(“I am not Useless”);
}

9. Calling Methods
Points
• Methods are created to provide service.
• Methods can be called whenever we
need their services.
• Methods in Java are a part of a class or
an object.
• Normally methods belong to an object
unless they are static
• We need to create an object of the class
that contains the method to be able to
use them.
Example
Class A
{
public void hi()
{
}
}
A obj = new A();
obj.hi();

10. Mechanism of Calling methods
points
• A method is called by:
• 1. Its name
• 2.Number and type of Arguments
• 3. Return Types.
• Note that if a method returns
something we need to prepare a
suitable container to hold the
returned value from the function
Exmaple
class A
{
public int add(int a)
{
}
}
A obj = new A();
int container = obj.add(3);