Data Structures and Algorithms in Java[1].pdf - Fulvio Frisone

2.3 Exceptions
Exceptions are unexpected events that occur during the execution of a program. An
exception can be the result of an error condition or simply an unanticipated input. In
any case, in an object-oriented language, such as Java, exceptions can be thought of
as being objects themselves.
2.3.1 Throwing Exceptions
In Java, exceptions are objects that are thrown by code that encounters some sort of
unexpected condition. They can also be thrown by the Java run-time environment
should it encounter an unexpected condition, like running out of object memory. A
thrown exception is caught by other code that "handles" the exception somehow, or
the program is terminated unexpectedly. (We will say more about catching
exceptions shortly.)
Exceptions originate when a piece of Java code finds some sort of problem during
execution and throws an exception object. It is convenient to give a descriptive
name to the class of the exception object. For instance, if we try to delete the tenth
element from a sequence that has only five elements, the code may throw a
BoundaryViolationException. This action could be done, for example,
using the following code fragment:
if (insertIndex >= A.length) {
throw new
BoundaryViolationException("No element at index " +
insertIndex);
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