{"id":6288,"date":"2018-01-23T13:07:59","date_gmt":"2018-01-23T07:37:59","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=6288"},"modified":"2026-05-07T12:08:23","modified_gmt":"2026-05-07T06:38:23","slug":"variables-in-java","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/variables-in-java\/","title":{"rendered":"Types of Variables in Java with Examples"},"content":{"rendered":"

Before studying what Variables in Java are, let’s go through some primary concepts in real life that mirror the concept of variables.<\/p>\n

Imagine it’s summer and you are very thirsty. You want to have water. But as soon as you are about to quench your thirst, you begin to observe that water is always in something. Right? It can be a bottle, it can be a glass, or it can be in a cup. These are containers or variables. They contain a value, in this case, water. However, the value of the container may change. This results in the name \u201cVariable\u2019 which means that the value inside it can change.<\/p>\n

Considering the example at hand, the tumbler can have anything, be it juice, water, or a milkshake. This is the basic concept of a variable.<\/p>\n

Java Variables<\/h3>\n

When Java executes a program, the values are stored in containers called variables. It is the name of a memory location.
\nIt is also a basic unit of storage.
\nVariables must be declared before they are used, and the changes in variables make actual changes in the memory location.<\/p>\n

In Java ,variables are declared as <datatype><variable_name>=<Variable_value><\/p>\n

For Example- int i=76, String s=\u201dDataFlair\u201d;<\/p>\n

Types of Variables in Java<\/h3>\n

The scope of a variable determines its visibility and lifetime within your program.<\/p>\n

Java variables are of 3 types:<\/strong><\/p>\n

1. Java Local Variable
\n2. Instance Variable in Java
\n3. Java Static Variable<\/p>\n

1. Local Variable in Java<\/h4>\n

A local variable is a variable that has a value within a particular method or a function. Outside the scope of the function, the program has no idea about the variable. Consider a real-life example, where you have an embarrassing nickname that is known to your parents. But no other person outside your house knows it, right?<\/p>\n

That is exactly how a local variable works. It is known locally. Hence the name. Local variables cannot be declared static.<\/p>\n

Example of Java Local variable:<\/strong><\/p>\n

class DataFlair {\r\n  int a = 9,\r\n  b = 10;\r\n  void LearnJava {\r\n    int local_j = 45; \/\/ A local variable\r\n    String s = \u201dDataFlair Training\u201d; \/\/A local variable\r\n  }\r\n}<\/pre>\n
A local variable cannot be accessed directly outside a function.<\/p>\n
2. Java Instance Variable<\/h4>\n
Instance variables are those that are declared inside the body of a class but not within any methods. These differ with each instance of the class created, although they have the same identity.<\/p>\n
Example of an instance variable in Java:<\/strong><\/p>\n
import java.io. * ;\r\nclass Person {\r\n  int height,\r\n  weight; \/\/ Instance Variables\r\n  Person(int h, int w) {\r\n    this.height = h;\r\n    this.weight = w;\r\n  }\r\n  void run() {\r\n    System.out.println(\u201cHuff Puff\u201d);\r\n  }\r\n  void print() {\r\n    System.out.println(\u201cNow my weight is\u201d + this.weight);\r\n  }\r\n  public static void main(String[] args) throws IOException {\r\n    Person A = new Person(170, 65);\r\n    A.run();\r\n    A.print();\r\n  }\r\n}<\/pre>\n
Output:<\/strong><\/p>\n
Huff Puff
\nNow my weight is 65.<\/div>\n
The variables height and weight are the instance variables, i,e, they are unique for every instance created.<\/p>\n
These cannot be initialized with a static keyword. However, one instance of the Person class cannot share the details of another instance of the same class.<\/p>\n
3. Static Variables in Java<\/h4>\n
What if we want a variable that is shared across all the instances of a class? That’s where static variables come in. These are class- level variables which are the same for all the instances generated. As soon as a class loads, the static variables get their initialization.<\/p>\n
Static Variables are declared in the following way:
\nstatic <variable_name> =<variable_value><\/strong><\/p>\n
Example of a static variable in Java:<\/strong><\/p>\n
import java.io. * ;\r\nclass DataFlair {\r\n  static int studentCount;\r\n  DataFlair() {\r\n    studentCount = 15;\r\n  }\r\n  void addStudent() {\r\n    studentCount++;\r\n  }\r\n\r\n  public static void main(String[] args) throws IOException {\r\n    DataFlair java = new DataFlair();\r\n    DataFlair python = new DataFlair();\r\n    java.addStudent();\r\n    python.addStudent();\r\n    System.out.println(\"Total Students \" + studentCount);\r\n  }\r\n}<\/pre>\n
Output:<\/strong><\/p>\n
Total Students 17<\/div>\n
Hence, we observe that the static variable <\/a>is shared across both the instances created in Java and Python for the class DataFlair. This also helps us in counting the total number of students who have joined DataFlair!<\/p>\n
Declaring Java Variables<\/h3>\n
In Java, the variables have to be declared previously because, unlike Python, Java is a statically typed language. That means before its use in the program. If a variable is used and then declared, it outputs an error. The reason for this is that the compiler starts executing the lines from top to bottom. As soon as the compiler gets an initialization command, it reserves memory with the name mentioned in the program. If a particular variable is used in a line and it is not declared with a proper data type in any of the previous lines, then the compiler throws an error.<\/p>\n
Example program to illustrate declaring variable concepts:<\/strong><\/p>\n
import java.io.IOException;\r\n\r\nclass DeclareVar {\r\n  public static void main(String[] args) throws IOException {\r\n    int a = 10,\r\n    b = 4;\r\n    System.out.println(c); \/\/ This accesses c before its declaration. \r\n    int c = 74;\r\n  }\r\n}<\/pre>\n
Output:<\/strong><\/p>\n
DeclareVar.java:7: error: cannot find symbol
\nSystem.out.println(c);
\n^
\nsymbol: variable c
\nlocation: class DeclareVar
\n1 error<\/div>\n
Variable Naming Conventions in Java<\/h3>\n
Selecting clear and descriptive variable names is crucial for enhancing code readability and maintainability. Strive to use names that accurately reflect the variable’s purpose. For instance, instead of x, a more descriptive name might be customerAge or totalCost. This practice makes your code easier to understand for both yourself and your fellow programmers, especially when revisiting code after extended periods.<\/p>\n
There are particular conventions to be followed when naming variables to enhance the readability of the program.
\nSome of them are:<\/p>\n
a.<\/strong> Its convention to start the names of a variable with an alphabet rather than an underscore or a dollar sign<\/p>\n
b.<\/strong> Variable names can have any alphabet or numbers after the first letter. However, spaces are not allowed.<\/p>\n
c.<\/strong> The reserved words such as int, static, void, and so on cannot be used as variable names.<\/p>\n
d.<\/strong> Constant values can be stored in variables that are named in \u201cALL_CAPS\u201d.<\/p>\n
e.<\/strong> Variables which need two distinct words can be written together using camelCase.<\/p>\n
Example<\/strong>– int amountOfWater=1000; \/\/This preserves the meaning of the variable.<\/p>\n
Summary<\/h3>\n
From storing the numbers to storing the strings, we use variables at almost every point of programming. Now we have understood why we need variables and what are the things to keep in mind while declaring variables.<\/p>\n
However, we also got to know about different types of variables and the accessibility of variables across programs. In this article, we learned about the various kinds of variables in Java and their uses.<\/p>\n
In programming, the cautious and efficient use of variables leads to faster outputs. In programming, variables play an efficient role in memory optimization. Variables are key in programming, and without variables, storing data would be impossible.
Before studying what Variables in Java are, let’s go through some primary concepts in real life that mirror the concept of variables. Imagine it’s summer and you are very thirsty. You want to have...<\/p>\n","protected":false},"author":7,"featured_media":78482,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[32],"tags":[3641,6831,7739,16454,8364,12661,13791,15124,15489],"class_list":["post-6288","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java","tag-declaring-java-variable","tag-instance-variables-in-java","tag-java-variable-declaration","tag-java-variable-example","tag-local-variables-in-java","tag-scope-of-variables-in-java","tag-static-variables-in-java","tag-types-of-variables-in-java","tag-what-are-java-variables"],"yoast_head":"\nTypes of Variables in Java with Examples - DataFlair<\/title>\n<meta name=\"description\" content=\"Variables in Java is used to store the value of element. There are 3 types of variable: Local, global, static. 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