Throwing Light on Throwables

Introduction

A Throwable object represents an exception or error that occurs during program execution which disrupts the normal flow of the program. These objects are instances of subclasses of the Throwable class- errors and exceptions.

Errors vs. Exceptions

Errors are abnormal conditions that occur in the JVM resulting in its termination. They are unrecoverable and cannot be caught by the program. Examples include OutOfMemoryError, StackOverflowError, and LinkageError.

Exceptions, on the other hand, are a subclass of Throwable that represent abnormal conditions that occur during the program’s execution. They disrupt the normal flow of the program and require special handling. Examples include IOException, NullPointerException, and RuntimeException.

Handling Throwables

When a method throws an exception, it must either handle it using a try-catch block or declare it in its throws clause. The try-catch statement consists of a try block followed by one or more catch clauses. The try block contains the code in which the exception is likely to occur, and the catch clause contains code to handle the exception that results from the try block. It is important to ensure that the exception is handled at the appropriate level of abstraction. For example, if a method throws an exception, it should be handled in the calling method rather than within the method itself.

The throws clause is used to declare the exceptions that can be thrown by a method. It indicates to the caller of the method the type of exceptions that the method can throw. A method can declare multiple exceptions using a comma-separated list. If an exception declared in this statement is not handled by the method, it propagates up the call stack until it is handled by a try-catch block or until it reaches the top of the stack.

Conclusion

Throwables are an essential aspect of Java programming. Understanding how to handle exceptions and errors can help write code that is more robust and reliable. By correctly handling throwables, developers can ensure that their code can recover gracefully from unforeseen circumstances and provide a better user experience.