java中关于编译期间和程序运行期间的对象的处理

public class Test {
	static class A {
		public int i = 1;
		public static void showI() {
			System.out.println("1");
		}
	}
	static class B extends A {
		public int i = 2;
		public static void showI() {
			System.out.println("2");
		}
	}
	public static void main(String[] args) {
		int[] num  =new int[10];

        System.out.println(num[10]);
		//编译期间a已经绑定了i和showI
		A a = new B();
		System.out.println(a.i);//1
		a.showI();//1
		//运行期间c绑定到子对象d上了
		C c = new D();
		System.out.println(c.i);//3 变量没有多态性 所以是3
		System.out.println(c.getI());//4
		c.showI();//4
	}
}
class C{
	public int i = 3;
	public void showI(){
		System.out.println("3");
	}
	public int getI() {
		return i;
	}
	public void setI(int i) {
		this.i = i;
	}
}

class D extends C{
	public int i = 4;
	public int getI() {
		return i;
	}
	public void setI(int i) {
		this.i = i;
	}
	public void showI(){
		System.out.println("4");
	}
}