-static的作用
使用示例如下,注意内部类的使用区别:
public class staticDemo { static int attr; static { attr =1; } static int func(){ return attr; } static class staticInnerClass{ } class nonStaticInnerClass{ } public static void main(String [] args){ staticDemo.staticInnerClass instance1 = new staticDemo.staticInnerClass(); staticDemo.nonStaticInnerClass instance2 = new staticDemo().new nonStaticInnerClass(); } }
-类的四种权限
private
default
protected
public
-重载属于编译期多态,override是运行期多态
-char和short都是16位,有什么区别?
前者无符号位