虚拟机产生异常的原由与处理
产生原因：1。由于不正常的语句背虚拟机检测到。抛出异常在语句执行点。可能情况有：违反语义的操作如数组过界；资源越界；连接程序时出错
2。java代码执行throws语句
3。异步异常：ThreadGroup的stop()方法调用与虚拟机内部发生错误。
处理异常：封闭try内部代码转到靠try最近的catch语句中，在没有catch语句情况下该线程停止，只有finnaly语句执行；并且当其线程父类
ThreadGroup调用unCatchedException后才终止该线程。
异常分类：（java.lang下）
Exception:
AclNotFoundException, ActivationException, AlreadyBoundException, ApplicationException,
AWTException, BackingStoreException, BadLocationException, CertificateException, ClassNotFoundException,
CloneNotSupportedException, DataFormatException, DestroyFailedException, ExpandVetoException,
FontFormatException, GeneralSecurityException, GSSException, IllegalAccessException,
InstantiationException, InterruptedException, IntrospectionException, InvalidMidiDataException,
InvalidPreferencesFormatException, InvocationTargetException, IOException, LastOwnerException,
LineUnavailableException, MidiUnavailableException, MimeTypeParseException, NamingException,
NoninvertibleTransformException, NoSuchFieldException, NoSuchMethodException, NotBoundException,
NotOwnerException, ParseException, ParserConfigurationException, PrinterException, PrintException,
PrivilegedActionException, PropertyVetoException, RefreshFailedException, RemarshalException,
RuntimeException, SAXException, ServerNotActiveException, SQLException, TooManyListenersException,
TransformerException, UnsupportedAudioFileException, UnsupportedCallbackException,
UnsupportedFlavorException, UnsupportedLookAndFeelException, URISyntaxException,
UserException, XAException
其中不受检测的运行期异常类：RuntimeException类
ArithmeticException, ArrayStoreException, BufferOverflowException, BufferUnderflowException,
CannotRedoException, CannotUndoException, ClassCastException, CMMException,
ConcurrentModificationException, DOMException, EmptyStackException, IllegalArgumentException,
IllegalMonitorStateException, IllegalPathStateException, IllegalStateException, ImagingOpException,
IndexOutOfBoundsException, MissingResourceException, NegativeArraySizeException, NoSuchElementException,
NullPointerException, ProfileDataException, ProviderException, RasterFormatException, SecurityException,
SystemException, UndeclaredThrowableException, UnmodifiableSetException, UnsupportedOperationException
Error:
AssertionError, AWTError, CoderMalfunctionError, FactoryConfigurationError, LinkageError, ThreadDeath,
TransformerFactoryConfigurationError, VirtualMachineError
(未完)