In Java terms, errors are
thrown to an event handler which catches it and
processes it.
Thus, exception objects are always instances of
the Throwable class and can be thrown from a routine
to an error handler. In the following example, we see that the
readLine() method might throw an IOException error object if it has
trouble reading a line.
public String readLine() throws IOException
It is also of interest to know that a
method may throw multiple errors by listing them as a comma separated
list after the "throws" keyword.
Of course, a method may perform correctly without
throwing an error. The throws portion just allows the method to deal
with the "other" cases.
You can also throw your own error objects
including both those available through the JDK as well as ones you
create yourself.