The document discusses Java exceptions. It defines an exception as an event that disrupts normal program flow. When an error occurs in a method, the method creates an exception object and passes it to the runtime system. The code that handles exceptions is called an exception handler. It then describes the five keywords used for exception handling in Java: try, catch, finally, throw, and throws and their purposes. Finally, it discusses the advantages of exception handling, such as maintaining normal program flow when exceptions occur, and the hierarchy of Java exception classes.