The Difference between Checked and Unchecked Exceptions in Java
Java is a popular programming language used extensively in application development. When it comes to error handling in Java, exceptions play an essential role. Exceptions refer to errors or malfunctions that occur during a program’s execution, leading to program disruption. Two main types of exceptions in Java are checked and unchecked exceptions. In this article, we’ll discuss the differences between them.
Checked Exceptions
A checked exception is an exception that must be declared by a developer in the method or function signature using the “throws” keyword. They are checked at compile time, and the compiler will verify whether the exception is handled or propagated to the calling method. Checked exceptions are commonly used for error handling scenarios where the application can recover from the exception.
For example, when reading data from a file, it’s possible that the file may not exist or may not have proper read permissions. In such a scenario, the IOException is a checked exception that must be handled. The developer can recover from this exception by displaying an error message, asking the user to input a different file name, or perhaps creating a new file with a default configuration.
Unchecked Exceptions
An unchecked exception, on the other hand, is an exception that occurs at runtime and is not checked by the compiler. They are not required to be explicitly declared in the method signature, and the developer uses the “try-catch” block to handle them. The exceptions that extend RuntimeException or Error classes are unchecked exceptions.
Unchecked exceptions occur due to programming mistakes, such as null pointer exception, divide by zero, etc. They typically indicate serious programming flaws, and it’s not possible to recover from them. Instead, the application should terminate when an unchecked exception is thrown.
Unchecked exceptions should be used judiciously and only when the developer believes that the application cannot recover from an exception. In scenarios where there is a possibility of user error or resource unavailability, checked exceptions should be used.
Conclusion
In conclusion, checked and unchecked exceptions in Java serve different purposes. Checked exceptions are used to handle errors that can be recovered from, while unchecked exceptions signify programming mistakes and other fatal errors that usually terminate the application. By understanding the differences between checked and unchecked exceptions, developers can effectively handle error scenarios and make their application more reliable and stable.
Table difference between checked and unchecked exception
| Checked Exceptions | Unchecked Exceptions |
|---|---|
| Checked exceptions are the exceptions that are checked by the compiler at the time of compilation. | Unchecked exceptions are the exceptions that are not checked by the compiler during the compilation process. |
| Checked exceptions occur due to external factors and not due to programming errors. | Unchecked exceptions occur due to programming errors such as null pointer, division by zero, etc. |
| Checked exceptions are recoverable and can be handled using try-catch block. | Unchecked exceptions are not recoverable and cannot be handled using try-catch block. |
| Checked exceptions are used for error handling that can be predicted and recovered from, such as file not found, network errors, etc. | Unchecked exceptions are used for errors that are difficult or impossible to recover from, such as runtime errors, logic errors, etc. |
| Checked exceptions must be declared in the method signature or handled at the point of compilation. | Unchecked exceptions do not need to be declared in the method signature or handled at the point of compilation. |