Super Keyword Example in Java

Introduction

Super Keyword is a classic Java console program that demonstrates the concept with complete source code and sample output. Practical numeric and utility programs — primes, factorial, palindrome and similar classics.

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

• Super keyword is used inside a sub-class method definition to call a method defined in the super class.
• Private methods of the super-class cannot be called.
• Only public and protected methods can be called by the super keyword.
• It is also used by class constructors to invoke constructors of its parent class.

Syntax

super.method_name();

Super Keyword Example Program

class Main{  
	int distance=50;  
}  
class SuperKeywordDemo extends Main{  
	int distance=100;  
	void display(){  
		System.out.println("distance is: "+super.distance);
	}  
	public static void main(String args[]){  
		SuperKeywordDemo obj=new SuperKeywordDemo();  
		obj.display();  
	}  
}

Sample Output

distance is: 50

When to use

Use this super keyword 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 distance=50; updates a variable used in the calculation or output.

3. int distance=100; 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. SuperKeywordDemo obj=new SuperKeywordDemo(); updates a variable used in the calculation or output.

6. Compare your console output with the sample output for Super Keyword 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.