JAVA 的checked异常和unchecked异常

• 
  什么是unchecked异常?

  即RuntimeException（运行时异常）
  不需要try...catch...或throws 机制去处理的异常
  
  

  • 列举最常用的五种RuntimeException:????

    这是JAVA认证考试中最常见的题目,事实上,runtime exception中最常见的,经常碰到的,也就5,6种,如下:
    

    ?ArithmeticExceptionint a=0;
    int b= 3/a;?ClassCastException：Object x = new Integer(0);
    System.out.println((String)x);?IndexOutOfBoundsException
    ????ArrayIndexOutOfBoundsException,
    ????StringIndexOutOfBoundsException?
    int [] numbers = { 1, 2, 3 };
    int sum = numbers[3];IllegalArgumentException
    ????NumberFormatException
    int a = Interger.parseInt("test");
    NullPointerExceptionextends
    ?
    
    • 除了RuntimeException，其他继承自java.lang.Exception得异常统称为Checked Exception,他们有多少种呢?

      下面是JDK API中列出的异常类:
      除了RuntimeException以外的,都是checked Exception
      

      java.lang.Object
      ??java.lang.Throwable
      ??????java.lang.Exception
      所有已实现的接口：
      Serializable
      直接已知子类：
      AclNotFoundException, ActivationException, AlreadyBoundException, ApplicationException, AWTException, BackingStoreException, BadAttributeValueExpException, BadBinaryOpValueExpException, BadLocationException, BadStringOperationException, BrokenBarrierException, CertificateException, ClassNotFoundException,?CloneNotSupportedException, DataFormatException, DatatypeConfigurationException, DestroyFailedException, ExecutionException, ExpandVetoException, FontFormatException, GeneralSecurityException, GSSException, IllegalAccessException, IllegalClassFormatException, InstantiationException, InterruptedException, IntrospectionException, InvalidApplicationException, InvalidMidiDataException, InvalidPreferencesFormatException, InvalidTargetObjectTypeException, InvocationTargetException, IOException, JAXBException, JMException, KeySelectorException, LastOwnerException, LineUnavailableException, MarshalException, MidiUnavailableException, MimeTypeParseException, MimeTypeParseException, NamingException, NoninvertibleTransformException, NoSuchFieldException, NoSuchMethodException, NotBoundException, NotOwnerException, ParseException, ParserConfigurationException, PrinterException, PrintException, PrivilegedActionException, PropertyVetoException, RefreshFailedException, RemarshalException,?RuntimeException,?SAXException, ScriptException, ServerNotActiveException, SOAPException, SQLException, TimeoutException, TooManyListenersException, TransformerException, TransformException, UnmodifiableClassException, UnsupportedAudioFileException, UnsupportedCallbackException, UnsupportedFlavorException, UnsupportedLookAndFeelException, URIReferenceException, URISyntaxException, UserException, XAException, XMLParseException, XMLSignatureException, XMLStreamException, XPathException
      
      
      
      
      
      
      

      ?