第一代编程语言纯机器语言第二代编程语言汇编第三代编程语言C、Pascal等面向过程的语言C++、java等面向对象的语言OC同样是面向对象的语言Mac OS X 支持GC, iOS不支持GC需要手动管理内存开发环境必须是Mac OSXcode包括：Xcode appiPhone SDKiPhone SimulatorInstruments 

Toast 类似弹出提示信息Radio group添加一个监听器每个多选按钮添加一个监听器 

hashCode() 和toString()方法都存在于Object类中 

简单静态工厂方法模式

异常是在运行时产生的，跟编译没太大关系。异常的类都是JDK提供的Throwable包括Exception和ErrorError：会导致虚拟机关闭Exception:          RuntimeException（运行时异常）          编译时异常    finally 通常用来清理  

异常是中断了正常指令流的事件，当产生了这样的事件，java虚拟机就生成异常对象throws: 本函数不处理，而是调用本函数时处理异常

I: input  O: output 输入输出是相对于Java程序本身1.分类输入流输出流2.分类字节流字符流3.分类节点流处理流  InputStream:int read(byte [] b, int off, int len)返回值是读取了多少字节的数据OutputStream:void write(byte [] b, int off, int len)调用String对象的trim方法，将会去掉这个字符串的首尾空格和空字符

chapter 4 The King James Bible or light there be light reading In 1611 'the powers that be' 'turned the world upside down' with a 'labour of love' a new translation of the bible. A team of scribes with the 'wisdom of Solomon'-'went the extra mile' to make King James's translation 'all things to all men' whether from their 'heart's desire' ' to fight the good fight' or just for the 'filthy lucre'.This sexy new Bible went 'from strength to strength' getting to 'the root of the matter' in a language even 'the salt of the earth' could understand. 'The writing wasn't on the wall', it was in handy little books and with 'fire and brimstone' preachers reading from it in every church, its words and phrases 'took root' to the ends of the earth' well at least the ends of Britain.The King James Bible is the book that taught us that 'a leopard can't change its spots', that 'a bird in the hand is worth two in the bush', that 'a wolf in sheep's clothing' is harder to spot than you would imagine, and how annoying it is to have 'a fly in your ointment'.In fact, just as 'Jonathan' begat Meribbaal; and Meribbaal begat Micah.Pithon', the King James Bible begat a whole glossary of metaphor and morality that still shapes the way English is spoken today. Amen