Methods in Java

The Methods in Java are the collection of statements that are executed when the method is called. By using the methods, the complexity of writing the code decreases.

The method consists of the block of code to perform a task. The methods are used for the Reusability feature i.e., We can be able to call the methods for number of times according to our problem instead of writing the same code for a greater number of times.

The main() method in Java is the most important method as the execution of a Java program start with the main method.

Declaration of Methods in Java

The Method declaration or the Method Signature has the following components

• Return data type
• Name of Method
• Parameters

We can also include the access modifiers, if not mentioned it takes the “Default access modifier/ specifier”.

Syntax:

Access_modifer return_datatype  Method_Name(Parameters)

Example:

public int Matrix (int a , int b)

Calling a Method in Java

The method is executed only when the method is called. The basic way of calling method is, writing the method name then parenthesis i.e. ().

Example:

import java.io.*;
class MethodDemo
{
static void Method()
{
System.out.println(“Method Invoked”);
}
public static void main (String args[])
{
Method();
}
}   

Output:

Method Invoked

The method which doesn’t return any value is declared by the void data type.

Passing parameters in Methods

In the process of Calling a method, we can give the parameters inside the parenthesis ().

//Example program for the Parameterized Method
import java.io.*;
class MethodDemo
{
static void method(int a)
{
System.out.println(“The Number is”+a);
} 
public static void main(String args[])
{
method(10);
}
} 

Output:

The Number is 10

Types of Methods

There are two types of Methods they are,

• Predefined Methods.
• User- defined Methods.

Predefined Methods:

The predefined methods in Java are the methods which are prewritten in the Java libraries. It is also called as built-in Method. Examples of Predefined methods are length() , sqrt(), equals() etc.

Example:

class PreMethod
{
public static void main(String args[])
{
System.out.println(“Max Number is ”+Math.max(9,7));
}
}

Output:

Max Number is 9  

User-defined Methods

The user-defined methods are the methods which are written by the user/programmer.

Creation of User-defined method

Example Program for User defined method checking a person is eligible for vote or not.

Code:

class MDemo
{
public static void Elec(int x)
{
if(x>18)
{
System.out.println(“Eligible”);
}
else
{
System.out.println(“Not- Eligible”);
}
}  
// calling the method in main method
public static void main(String args[])
{
Elec(20); // calling method 
}
}  

Output:

Eligible

The above program consists of method Elec which is used to check the eligibility for casting the vote or not. The Elec method is being called in the Main method with parameters “x”.

Method Overloading

If the class consists of multiple methods with the same name, then it is called “Method Overloading”.

Example:

public class Ex
{
public static void main(String args[])
{
int A =10;
int B=12;
double d1 = 10.25;
double d2 = 18.50;
Max(A,B);
Max(d1,d2);
}
public static void Max(int x , int y)
{
if(x>y)
{
System.out.println(“Maximum Number : ”+x);
}
else
{
System.out.println(“Maximum Number : ”+y);
}
}
public static void Max(double i, double j)
{
if(i>j)
{
System.out.println(“Maximum Number : ”+i);
}
else
{
System.out.println(“Maximum Number : ”+j);
}
}


} 

Output:

Maximum Number: 12
Maximum Number: 18.50

In the example, we have created the two methods with the same name “Max” and the parameters of the two methods are different i.e., the first method parameters are given as integer datatype and second method parameters are given as double datatype. The program executes perfectly without any errors.

Abstract Methods

The abstraction is the process of hiding the unnecessary information or code to the user. To achieve the abstraction, we use the abstract methods.

For Example, if the user doesn’t want to see any information about the code and all the clumsy stuff in the code so we use the abstraction to show the relevant details to the user which are useful to them.

Creating the Abstract Methods

The Abstract methods are declared by using the “abstract” keyword before creating a method.

The Abstract class can consist of both Abstract method and Concreate methods. The Concrete methods are the just the regular methods.

The Abstract methods doesn’t create any new object, but they can be able to create the references.

The Abstraction is done by the concept of using the inheritance.

Example:

abstract class Dem
{
public abstract void connect();
public void check()
{
System.out.println(“Checking Connections”);
}
} 
class Be extends Dem
{
public void connect()
{
System.out.println(“Bluetooth Connected”);
}
}
class Mainn 
{
public static void main(String args[])
{
Be b = new Be();
b.check();
b.connect();
}
}

Output:

Checking Connections
Bluetooth Connected

Summary

The methods in Java are the collection of statements which are enclosed in the block i.e., {} are executed by the call of the method. There are two types of methods they are, Predefined methods and User defined methods. In the predefined methods the methods are already prewritten the Java libraries. The User defined methods are the methods which are written by the user or the Programmer. There is a special type of method that is abstract method, the abstract method is used to achieve the abstraction in the program.