How to Use the Java Scanner Class

If You Are Stepping Into the World of Java Programming, You Will Immediately Realize That Input Plays a Vital Role in Creating Dynamic Applications. One of the Essential Tools You Have Available Is a Java Scanner. In This Comprehensive Guide, We Will Explore the Intricacies of the Java Scanner Class, Its Functions, Methods, and Best Practices. So, Let’s Begin the Journey of Mastering This Indispensable Tool.


Java Scanner Is a Class in the java.util Package That Allows You to Read and Parse Different Types of Input From Different Sources. It Provides a Versatile Way to Interact With User Input, Files, or Any Other Input Stream. Whether You Want to Read Integers, Floating-Point Numbers, or Strings, the Java Scanner Class Provides a Convenient Solution.

Java Scanner – Video for You

Importing Java Scanner Class

Before Using the Scanner Class, You Must Import It Into Your Java Program. This Can Be Done With the Following Import Statement:

import java.util.Scanner;

Creating a Scanner Object

To Start Using the Java Scanner, You Need to Create a Scanner Object. This Object Serves as a Gateway to Read Input From Various Sources. Here’s How You Can Make It:

Scanner scanner = new Scanner(;

In This Example, We Have Created a Scanner Object That Reads Input From the Standard Input Stream (

Reading Different Data Types

Read Integer

You Can Use the Scanner Class to Read Integers From an Input Stream. Here Is a Simple Example:

int number = scanner.nextInt();

This Code Snippet Reads the Integer Entered by the User and Stores It in the Number Variable.

Reading Floating-Point Numbers

To Read Floating-Point Numbers, Use the Nextdouble() Or Nextfloat() Methods:

double decimal = scanner.nextDouble();

Reading Strings

To Read Strings, You Can Use the Next() Or Nextline() Methods:

double decimal = scanner.nextDouble();

Handling Input Errors

Input Errors Can Occur When Users Enter Unexpected Values. To Handle Such Errors Gracefully, You Should Implement Error-Checking Mechanisms Such as Exception Handling.

Turning off the Scanner

It Is a Good Practice to Close the Scanner When You Are Finished to Free up System Resources. You Can Do This With the Close() Method:


Scanner vs Bufferedreader

While the Scanner Class Is Excellent for Simple Input Tasks, Consider Using Bufferedreader for Better Performance and Efficiency for More Complex Scenarios or Reading From Files.

Use Case for Java Scanner

Java Scanner Finds Applications in a Wide Range of Scenarios, From Simple Console Input to Complex Data Parsing in File Processing.

Performance Considerations

When Working With Large Amounts of Input Data, It Is Essential to Optimize Your Code to Avoid Performance Bottlenecks.

Common Mistakes to Avoid

Avoid Common Mistakes Like Not Closing the Scanner, Not Handling Input Errors, or Using Incorrect Data Type Conversion Methods.

Best Practices for Java Scanner

Follow Best Practices Such as Using Meaningful Variable Names, Documenting Your Code, and Organizing Input Validation Logic Effectively.

Java Scanner Example

Let’s Look at a Practical Example of Using the Java Scanner to Create a Basic Console-Based Calculator.

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(;

        System.out.print("Enter the first number: ");
        double num1 = scanner.nextDouble();

        System.out.print("Enter the second number: ");
        double num2 = scanner.nextDouble();

        System.out.println("Sum: " + (num1 + num2));
        System.out.println("Difference: " + (num1 - num2));
        System.out.println("Product: " + (num1 * num2));
        System.out.println("Quotient: " + (num1 / num2));

Java Scanner Example

Java Scanner vs Other Languages

The Java Scanner Is a Powerful Tool, but It’s Important to Understand How It Compares to Similar Features in Other Programming Languages.

Java Scanner and Localization

The Scanner Class Allows You to Specify the Location for Input, Making It Adaptable to Different Regions and Languages.


In This Guide, We Have Explored the Basic Usage of the Java Scanner Class From Basic to Advanced Techniques. As a Java Developer, Mastering the Scanner Class Will Enable You to Create Interactive and Dynamic Applications That Handle User Input Efficiently.

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What is the Java Scanner class used for?

The Java Scanner Class Is Used to Read and Parse Various Types of Input From Various Sources, Including User Input and Files.

How do I handle input errors when using the Java Scanner?

Input Errors Can Be Handled Using Exception-Handling Mechanisms Such as Try-Catch Blocks.

What is the difference between Scanner and BufferedReader in Java?

While the Scanner Is Suitable for Simple Input Tasks, the Bufferedreader Is Preferred for More Complex Scenarios and File Processing Due to Its Superior Performance.

What common mistakes should be avoided when using a Java scanner?

Common Mistakes Include Not Closing the Scanner, Not Handling Input Errors, and Using Incorrect Data Type Conversion Methods.

What are the best practices for using a Java scanner?

Best Practices Include Using Meaningful Variable Names, Documenting Your Code, and Organizing Input Validation Effectively.

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