Variable, Constant & Literals in JAVA

In today’s topics, we will discuss Variable, Constant, and Literals in Java. These are very important concept that is necessary to remember before writing a Java program. Previously we also describe briefly various topics of Java such as Features of Java, History of Java, Difference between C++ & Java, and many more. So without wasting the time let’s dive into the topic:

Variable in JAVA

A variable is a data name that is used for storing a data value. The value of the variable may be changed during the program execution.

Example: – int number = 8;

Here ‘int’ is a data type, ‘number’ is a variable name and 8 is a value that it stores.

Rules for declaring a variable name

If the following conditions are satisfied the syntax of the variable is correct:

  • A variable must begin with a character without any space.
  • It must not begin with a digit.
  • It shouldn’t be a keyword.
  • Java variable name is case sensitive.
  • It doesn’t allow white space and commas.
  • After the above conditions are satisfied then it can contain alphabets, ‘&’ character, ‘_‘ character, and digits also.

Constant in JAVA

Constant is also a variable name but its value cannot be changed during program execution. If once we can assign a value to it then it cannot be changed. Simply we just need a ‘final’ keyword to declare a variable as a constant.

Example:- final double pi = 3.14;

Here ‘final’ is a keyword, ‘double’ is a data type, ‘pi’ is a variable name and 3.14 is a value that it stores.

Literals in JAVA

It is a constant value that can be assigned to the variable called a literal. Literal is a unique value to assign the variable. It is a representation of fixed value.

Example:- int a = 3;
float b = 4.9f;
char c = ‘A’;

Here ‘3’, ‘4.9’, ‘A’ are the literals.

There are mainly different types of literal available in Java i.e.:

  1. Integer Literal
  2. Floating point Literal
  3. Boolean Literal
  4. Character Literal

Integer literals

It is a numeric value that is assigned as a number. But it doesn’t contain any fractional or exponential part.

Example: – int a = 36;

Floating point Literal

These are the numeric literals that have in fractional format or exponential format.

Example: – float f = 7.6f;
double d = 56.9;

Boolean Literal

Boolean literals are used to initialize data with boolean value and boolean data type. It can store only the value ‘true’ or ‘false’.

Example:- boolean b = true;
boolean c = false;

Charachter Literals

These are the characters which are Unicode and these are enclosed within a single quote.

Example: – char e = ‘A’;

So this is all about the variables, constants & literals in Java. These are very useful concepts that are used in a java program. I hope this will help you. In the next upcoming post we will discuss another new topic of java, so wait for this will meet in the next post. Thank you.

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