Flow Control - SCJP Sun Certified Programmer for Java Platform SE6 - page 242

Java API Exceptions and Errors
The exam objectives state that you should be able to “recognize situations that will
result in any of the following being thrown,” and also “understand which of these are
thrown by the virtual machine and recognize situations in which others should be thrown
programmatically”
This section covers the details of each of the following Throwable types, all declared in
the java.lang package:
ArrayIndexOutOfBoundsException This exception is thrown by the JVM when your code
uses an illegal index to access an array.
ClassCastException This exception is thrown by the JVM when an attempt is made to
cast an object reference to a subclass of which it is not an instance.
IllegalArgumentException This exception is thrown programmatically to indicate that a
method has been passed an illegal or inappropriate argument.
IllegalStateException This exception is thrown programmatically when a method has
been invoked while the program is in an inappropriate state.
NullPointerException This exception is thrown by the JVM when an attempt is made to
use a null reference where an object is required.
NumberFormatException This exception is thrown programmatically when an attempt
is made to convert a string to a numeric type, but the string does not have the appropriate
format.
AssertionError This exception is thrown by the JVM when an assert statement fails.
ExceptionInInitializerError This exception is thrown by the JVM when an unex-
pected exception occurs in a static initializer.
StackOverflowError This exception is thrown by the JVM when the method call stack
overfl ows.
NoClassDefFoundError This exception is thrown by the JVM or ClassLoader when a
class needs to be loaded but no defi nition of the class can be found.
Note that you can programmatically throw any of these exceptions and errors, even
if an exception is typically thrown by the JVM. For example, if your code is aware
of a situation where an illegal array index is being used, you can instantiate a new
ArrayIndexOutOfBoundsException object and throw it using the throw keyword. However,
this is not something commonly done in Java.
The following section briefl y discusses each of these types of exceptions and
demonstrates situations where they might be thrown.