类成员
- 域:与类及对象相关联的数据变量,其中保存着类或对象的状态
- 方法
- 嵌套类和嵌套接口
类修饰符
类声明的前面可以指定类的特定属性
- public: 公共类,任何人都能声明该类的对象的引用或者访问它的公共成员,无该修饰符,类就只能在自己的包内访问
- abstract:抽象类,不能创建实例。通常,如果类中包含abstract方法,该方法就必须在子类中实现
- final:不能有子类
- strict floating point:定义为strictfp 的类要求其中所定义的浮点算法都进行精确的运算
一个类不能既是abstract 又是 final
可以有一个或者多个类修饰符,可以以任何顺序排列,但是一般遵循上述列出的排序
域
声明前也可以有修饰符
- 访问修饰符
- static
- final
- transient:与对象串行化有关
- volatile:与同步和内存模型有关
域-静态域(static)
也叫类变量,被所有对象共享。对象和类调用都可以,但是对象调用要尽量避免!以免认为是对象的成员
域-final域
final 变量在其值初始化之后就不能改变了-任何试图改变都导致编译时错误,如果final没有初始化,
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访问控制
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创建对象
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构造函数
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初始化块
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初始化块-静态初始化块
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方法
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方法-静态方法
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方法-方法调用
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方法-方法执行和返回
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方法-值传递
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方法-利用方法控制访问
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this
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重载方法
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main方法
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native方法
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