---
title: "How does a Java method throw an exception before it's called?"  
description: "How does a Java method throw an exception before it's called?"  
author: "Revati S Misra"  
published: 2023-07-28  
updated: 2023-07-29  
canonical: https://www.mindstick.com/forum/159351/how-does-a-java-method-throw-an-exception-before-it-s-called  
category: "java"  
tags: ["exception handling", "java", "exception"]  
reading_time: 1 minute  

---

# How does a Java method throw an exception before it's called?

How does a [Java](https://www.mindstick.com/articles/12214/web-development-company-in-india-laid-on-the-foundation-of-concrete-java-programming) [method](https://www.mindstick.com/forum/166/webservice-method) [throw an exception](https://www.mindstick.com/forum/159239/what-is-the-use-of-the-throw-keyword-to-manually-throw-an-exception-in-java) before it's called?

## Replies

### Reply by Aryan Kumar

A Java method cannot throw an [exception](https://www.mindstick.com/articles/1824/objective-c-exception-handling) before it's called. The `throw` keyword is used to throw an exception, and it is only valid within the body of a method. Therefore, a method cannot throw an exception before it's even called.

However, a method can **declare** that it can throw an exception. This is done using the `throws` keyword in the method declaration. For example, the following method declaration declares that the `readFile()` method can throw an `IOException` exception:

```plaintext
public void readFile(String fileName) throws IOException {
  // ...
}
```

This declaration does not actually throw an exception. It simply tells the compiler that the `readFile()` method **might** throw an exception. If the `readFile()` method does throw an exception, the exception will be thrown when the `readFile()` method is called.


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Original Source: https://www.mindstick.com/forum/159351/how-does-a-java-method-throw-an-exception-before-it-s-called

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