Variables In Java

In Java, variable is a name given to a memory location and this variable is associated with a value.

int x = 99;

int – data type
x – variable
99 – value

variable x holds integer values and its current value is 99.

Let’s see how to declare variables in Java

Syntax to declare a variable in Java:

data_type variable = value;

Example:

int x = 99;

Variable Naming Convention in Java:

Earlier we have learnt that Java is a Case Sensitive Language. Even variables have their own naming convention to follow.

1. Variable name can starts with special characters such as _ or $

Example:

int $myAge;

2. Variable name should begin with lower case leter

Example:

Wrong way: int Age;
Correct way: int age;

3. If the variable name consists of more than one word, it’s a best practice to capitalize the first letter of each subsequent word.

Example:

Wrong way: int myage;
Correct way: int myAge;

4. Variable name should not contain white spaces

Example:

Wrong way: int my Age;
Correct way: int myAge;

Types of Variables in Java:

There are three types of variables in Java.

1. Local variable
2. Instance variable
3. Class/Static variable

Let’s see each variable in detail.

Local Variable:

Local variable is a variable which we declare inside a Method. A method will often store its temporary state in local variables.

Instance Variable (Non-static):

Instance variable is a variable which is declared inside a Class but outside a Method. We don’t declare this variable as Static because these variables are non-static variables.

Class Variable (Static):

Class variable is a variable which is declared as Static. Additionally, the keyword final could be added to include that the value will never change.

Sample Program 1:

Sample Program 2:

Must Read: Java Tutorial

Rajkumar SM is a founder of SoftwareTestingMaterial. He is a certified Software Test Engineer by profession and blogger & youtuber by choice. He has an extensive experience in the field of Software Testing. He writes here about Software Testing which includes both Manual and Automation Testing. He loves to be with his wife and cute little kid 'Freedom'.

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