Instance of Operator Example in Java

Introduction

Instance Of Operator is a classic Java console program that demonstrates the concept with complete source code and sample output. Operators combine values, compare results and update variables — core skills for every Java program.

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

A binary operator that takes an object reference as its first operand and a class or interface as its second operand and produces a boolean result. The instanceof operator evaluates to true if and only if the runtime type of the object is assignment compatible with the class or interface.

Instance Of Operator Example Program

public class InstanceOfOperator {
	public static void main(String args[]){
		String str = "Julie";
		System.out.println("The input string is: "+str);
		boolean result = str instanceof String;  
		System.out.println( result );
	}
}

Sample Output

The input string is: Julie
true

When to use

Use this instance of operator 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. String str = "Julie"; updates a variable used in the calculation or output.

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

4. boolean result = str instanceof String; updates a variable used in the calculation or output.

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

6. Compare your console output with the sample output for Instance Of Operator 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.