Exceptions

In Java, an exception is an event that occurs during the execution of a program that disrupts the normal flow of instructions. Exceptions are typically caused by errors in code, such as division by zero, trying to access an array index that is out of bounds, or attempting to use an object reference that is null.

When an exception occurs, the Java runtime system creates an exception object that contains information about the error, such as the type of exception and a stack trace that shows the method calls that led up to the error. This exception object is then thrown, which means it is passed up the call stack until a method is found that can handle the exception.

Java provides a mechanism for handling exceptions called “try-catch” blocks. A “try” block contains the code that might throw an exception, and a “catch” block contains the code that handles the exception. If an exception is thrown in the “try” block, the Java runtime system searches for a “catch” block that can handle the exception. If a matching “catch” block is found, the exception is passed to that block and the code in the “catch” block is executed. If no matching “catch” block is found, the exception is passed up the call stack until it reaches the top level of the program, at which point the program terminates with an error message. Java also provides a “finally” block that can be used to execute code regardless of whether an exception is thrown or not. The “finally” block is guaranteed to be executed, even if the “try” block contains a return statement or the code in the “catch” block throws another exception. The “finally” block is often used to clean up resources, such as closing files or database connections.