Local Variable Example in Java

Introduction

Local Variable is a classic Java console program that demonstrates the concept with complete source code and sample output. Variables store state in a program. Java distinguishes local, instance and static (class) variables.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

Variables are identifiers associated with values. They are declared by writing the variable’s type and name, and are optionally initialized in the same statement by assigning a value. Local variables are visible only in the method or block they are declared. Local variables are created when a method is called and destroyed when the method exits.

Local Variable Example Program

public class LocalVariableDemo{ 
	public void add(){
		int num = 0;
		num = num + 7;
		System.out.println("The number is : " + num);
		System.out.println("This number is inside a method and hence has its scope only inside the method.");
	}
	public static void main(String args[]){
		LocalVariableDemo obj = new LocalVariableDemo();
		obj.add();
	}
}

Sample Output

The number is : 7
This number is inside a method and hence has its scope only inside the method.

When to use

Use this local variable example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. int num = 0; updates a variable used in the calculation or output.

3. num = num + 7; updates a variable used in the calculation or output.

4. A println / print call writes text to the console — part of the sample output below.

5. A println / print call writes text to the console — part of the sample output below.

6. LocalVariableDemo obj = new LocalVariableDemo(); updates a variable used in the calculation or output.

7. Compare your console output with the sample output for Local Variable to confirm the program behaves correctly.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.