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Variable in Java Programming with Example

Java Basic Concepts

In this lesson, we will learn about the variable in Java programming and its application, along with an example.

Definition of Variable in Java

A variable in Java is just a human-readable name used to store data in computer memory. A variable is also used in a computer program to store, read and change the data in computer memory.

A variable is also known as Identifier because it is used for identifying values in a computer program.

When you declare a variable in Java programming language, it means that you are asking the operating system to reserve a piece of memory with that variable name for storing data.

What is data?

Data is a collection of facts or figure or combination of both (facts and figure).

  • Facts - Any word that is consist of only alphabets is known as Facts. Example: john, mango, book, etc these words are consist of only alphabets. So each of them is a data but consist of Facts.
  • Figure - Any number whether it is whole number or real number is a Figure. Example: 15, 84.13, 5486, etc. So each of them is a data but consist of Figure.
  • Combination of Both (Facts and Figure) - Anything which is consist of Facts and Figure is known as Alphanumeric Text. Example: 13street, alpha56, dx14c5, etc. So each of them is a data but consist of Alphanumeric Text.

Let's see an example of variables and how it is used to store data in the computer's memory.

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Example

a = 5
b = "Apple"
a = 25

In the above example, a is used as a variable name to store the value (data) 5 in it. So we can say that the value of the variable a is 5. On line number 2 we have used another variable b to store the value (data) Apple (a value can be a number or text) so the value of the variable b is Apple.

On line number 3 we have changed the value of the variable a by storing a new value 25 in it. Now the new value of variable a is 25. So always remember that a variable can store only one value at a time if you store any other value in it then the previous value will be erased and the new value will be stored in it.