An exception in Java is an unwanted or unexpected event that occurs during the execution of a program, i.e. at run time, that disrupts the normal flow of the program’s instructions¹. An exception can be caused by various reasons, such as invalid user input, device failure, loss of network connection, code errors, etc¹.

When an exception occurs, the program creates an exception object that contains information about the exception, such as the name and description of the exception and the state of the program when the exception occurred¹. The exception object is then thrown to the runtime system, which tries to find a way to handle it.

Java provides a mechanism to handle exceptions using the try-catch-finally blocks². The basic syntax is:

The try block contains the code that may throw an exception. The catch block contains the code that handles the specific type of exception that occurs. You can have multiple catch blocks for different types of exceptions. The finally block contains the code that always executes, regardless of whether an exception occurs or not. The finally block is optional and can be omitted if not needed.

For example: