Java Exception Handling: Throws vs Try-Catch - Which One to Use?

Introduction

When writing code in Java, it is important to handle exceptions that may occur during runtime. This ensures that the program can gracefully handle unexpected errors and prevent it from crashing. There are two ways to handle exceptions in Java: using the "throws" keyword or using a "try-catch" block. In this article, we will explore the differences between these two methods and when to use each one.

Throws

The "throws" keyword is used to declare that a method may throw a particular exception. When a method is called that may throw an exception, the caller of the method must either handle the exception themselves or declare that they also may throw the exception using the "throws" keyword. This means that the exception will be propagated up the call stack until it is either handled or the program crashes.

Throws is useful when the exception cannot be handled within the method itself and must be handled by the calling method or the surrounding code. It can also be used to make the method signature more descriptive, indicating to the caller that the method may potentially throw a certain exception.

Try-Catch

A "try-catch" block is used to catch and handle exceptions that may occur within a block of code. The "try" block contains the code that may throw an exception and the "catch" block catches the exception and handles it accordingly. Multiple "catch" blocks can be used if different types of exceptions may occur.

Try-catch is useful when the code needs to handle the exception within the method itself. It allows for specific handling of different types of exceptions and can prevent the program from crashing by handling the exception in a more controlled manner.

When to use each one?

Whether to use "throws" or "try-catch" depends on the situation. If the exception cannot be handled within the method and must be propagated up the call stack, then "throws" should be used. On the other hand, if the exception can be handled within the method, then "try-catch" should be used.

It is important to note that both methods can be used together. If a method may potentially throw an exception but the exception can also be handled within the method, then both "throws" and "try-catch" can be used to provide a more robust exception handling mechanism.

Conclusion

In summary, "throws" and "try-catch" are two methods for handling exceptions in Java. "Throws" is used to declare that a method may throw an exception and propagate it up the call stack, while "try-catch" is used to catch and handle exceptions within a block of code. The decision to use one method over the other depends on whether the exception can be handled within the method or must be propagated up the call stack.