三大特征

public 公共的 公开的   private 私有的  不允许访问的   default 缺省的   默认的   友好  protected  受保护的

修饰符&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;本类&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;本包&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;不同包&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;其他<br>&nbsp;private&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;T&nbsp; &nbsp; &nbsp; &nbsp; F&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; F&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;F<br>&nbsp;默认的&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; T&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; F&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;F<br>&nbsp;protected&nbsp;&nbsp;&nbsp;&nbsp;T&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; T&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;F<br>&nbsp;public&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; T&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; T&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;T

尽可能的隐藏对象的内部细节，控制对象的修改及访问的权限

子主题

类与类之间的属性和方法的赠与和获得

特点