what does it mean to initialize a variable in java

Variable in Java is a information container that saves the data values during Coffee program execution. Every variable is assigned a data type that designates the type and quantity of value information technology tin can hold. Variable is a retentivity location name of the data.

A variable is a name given to a retention location. Information technology is the bones unit of storage in a program.

• The value stored in a variable tin can be changed during program execution.
• A variable is only a proper name given to a retentiveness location, all the operations done on the variable effects that memory location.
• In Java, all the variables must be declared earlier use.

How to declare variables?

We tin can declare variables in coffee every bit pictorially depicted below as a visual assist.

From the image, it can be hands perceived that while declaring a variable, we need to take care of two things that are:

1. Datatype: Type of data that tin be stored in this variable.

ii. Dataname: Proper noun was given to the variable.

In this way, a name tin can just exist given to a memory location. Information technology can be assigned values in two means:

• Variable Initialization
• Assigning value by taking input

How to initialize variables?

It can be perceived with the assist of 3 components that are as follows:

• datatype: Type of data that tin exist stored in this variable.
• variable_name: Proper name given to the variable.
• value: It is the initial value stored in the variable.

Illustrations:

float simpleInterest;  // Declaring float variable

int time = ten, speed = xx;  // Declaring and Initializing integer variable

char var = 'h';  // Declaring and Initializing character variable

Types of Variables in Java

Now let us talk over different types of variables which are listed equally follows:

1. Local Variables
2. Case Variables
3. Static Variables

Allow us discuss the traits of every variable been up hither in detail.

1. Local Variables

A variable defined within a block or method or constructor is called a local variable.

• These variables are created when the block is entered, or the role is called and destroyed subsequently exiting from the block or when the phone call returns from the function.
• The scope of these variables exists but within the cake in which the variable is declared. i.due east., we tin access these variables only within that block.
• Initialization of the local variable is mandatory earlier using information technology in the defined scope.

Java

import coffee.io.*;

class GFG {

public static void principal(String[] args)

{

int var = 10 ;

System.out.println( "Local Variable: " + var);

}

}

2. Example Variables

Case variables are not-static variables and are declared in a grade exterior any method, constructor, or cake.

• As instance variables are declared in a class, these variables are created when an object of the course is created and destroyed when the object is destroyed.
• Unlike local variables, nosotros may use admission specifiers for instance variables. If we do non specify any access specifier, then the default access specifier will be used.
• Initialization of Example Variable is not Mandatory. Its default value is 0
• Example Variable tin be accessed just past creating objects.

Java

import java.io.*;

grade GFG {

public Cord geek;

public GFG()

{

this .geek = "Shubham Jain" ;

}

public static void main(String[] args)

{

GFG proper noun = new GFG();

System.out.println( "Geek proper noun is: " + proper noun.geek);

}

}

Output

Geek name is: Shubham Jain

3. Static Variables

Static variables are also known equally Class variables.

• These variables are declared similarly as instance variables. The difference is that static variables are declared using the static keyword within a class outside any method constructor or cake.
• Unlike example variables, we can but accept one copy of a static variable per class irrespective of how many objects we create.
• Static variables are created at the start of plan execution and destroyed automatically when execution ends.
• Initialization of Static Variable is not Mandatory. Its default value is 0
• If we access the static variable like the Example variable (through an object), the compiler will show the alarm message, which won't halt the program. The compiler will supervene upon the object proper noun with the class name automatically.
• If we admission the static variable without the class name, the compiler will automatically append the form proper name.

Coffee

import java.io.*;

class GFG {

public static Cord geek = "Shubham Jain" ;

public static void main (Cord[] args) {

Arrangement.out.println( "Geek Name is : " +GFG.geek);

}

}

Output

Geek Proper name is : Shubham Jain

Differences betwixt the Case variable Vs. the Static variables

Now let usa exercise discuss the differences betwixt the Case variable Vs. the Static variables

• Each object will have its copy of the instance variable, whereas We can but have i copy of a static variable per form irrespective of how many objects we create.
• Changes made in an instance variable using one object will not exist reflected in other objects as each object has its own copy of the instance variable. In the case of static, changes volition be reflected in other objects equally static variables are common to all objects of a form.
• We can access example variables through object references, and Static Variables tin can be accessed directly using the form proper name.

Syntax: Static and instance variables

course GFG {     // Static variable     static int a;           // Instance variable     int b;         }        

Must Read:

• Rules of Variable Declaration in Java
• Scope of Variables in Coffee
• Comparison of static keyword in C++ and Coffee
• Are static local variables allowed in Coffee?
• Case Variable Hiding in Java

This article is contributed by Harsh Agarwal. If you like GeeksforGeeks and would like to contribute, yous can as well write an article using write.geeksforgeeks.org or post your commodity to review-team@geeksforgeeks.org. Encounter your commodity appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you desire to share more than information about the topic discussed above.

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