How to Fix Java Numberformatexception for Input String Error

1. Exceptions in Java
2. Handling numberformatexception for Input String in Java

This guide will tell you how you can prevent numberformatexception for input strings in Java. To understand it fully, we need to follow up on some of the basics of exception handling in Java. Let’s take a deeper look into it.

Exceptions in Java

The exception is a class that is used to handle some conditions. This class and its subclasses are a form of Throwable, indicating a certain condition that you need to catch while making applications.

Generally, you will see two types of exceptions. They are known as Checked Exception and Unchecked Exception.

Checked exceptions lie under the compile-time exceptions, while unchecked exceptions lie under RuntimeException. A programmer can make their custom exception by extending from the exception class.

Learn more about the exception here.

Handling numberformatexception for Input String in Java

In general, we handle the exception using the try...catch method. The numberformatexception for input string in Java is the same.

When sending a string as input and parsing it into an integer, it must throw a numberformatexception. You can avoid the error by handing it in using the try...catch methods.

Take a look at the following self-explanatory code.

import java.util.*;
public class Main {
  public static void main(String args[]) {
    String var = "N/A";

    // When String is not an integer. It must throw NumberFormatException
    // if you try to parse it to an integer.
    // we can avoid from Exception by handling Exception.
    // Exception Is usually Handle by try Catch Block.
    try {
      int i = Integer.parseInt(var);
      // if var is not a number than this statement throw Exception
      // and Catch Block will Run
      System.out.println("Number");
    } catch (NumberFormatException ex) { // handling  exception
      System.out.println(" Not A Number");
    }
  }
}

Output:

Not A Number

In the above code, you can see that parsing the var string will not work. It’s a condition that we need to check.

So, using the try...catch block, we handled it. If the string value is not a number, then the catch block will run.