第一题:
class Parent
{
public void nonStaticMethod()
{
System.out.println("Parent's Non-Static Method is Called");
}
public static void staticMethod()
{
System.out.println("parent's static method is called");
}
}
class Child extends Parent
{
public void nonStaticMethod()
{
System.out.println("child's non-static method is called");
}
public static void staticMethod()
{
System.out.println("child's static method is called");
}
}
public class Test
{
public static void main(String args[])
{
Parent p1 = new Parent();
Parent p2 = new Child();
Child c = new Child();
System.out.print("Parent.static: ");
Parent.staticMethod();
System.out.print("p1.static: ");
p1.staticMethod();
System.out.print("p2.static: ");
p2.staticMethod();
System.out.print("p1.nonStatic: ");
p1.nonStaticMethod();
System.out.print("p2.nonStatic: ");
p2.nonStaticMethod();
System.out.print("Child.static: ");
Child.staticMethod();
System.out.print("c.static: ");
c.staticMethod();
System.out.print("c.nonStatic: ");
c.nonStaticMethod();
}
}
问题1.
//Parent.static:parent's static method is called;
//p1.static:parent's static method is called;
//p2.static:parent's static method is called 结果为啥不是p2.static:child's static method is called;
//p1.nonStatic:Parent's Non-Static Method is Called;
//p2.nonStatic:child's non-static method is called;
// Child.static:child's static method is called;
//c.static: child's static method is called;
//c.nonStatic:child's non-static method is called;
第二题:
class ExtendDemo2
{
public static void main(String[] args)
{
Zi z=new Zi();
z.show();
}
}
class Fu
{
static void show()
{
System.out.println("123");
}
}
class Zi extends Fu
{
void show()
{
System.out.println("234");
}
}
运行结果为:
D:\延飞>javac ExtendDemo2.java
ExtendDemo2.java:21: 错误: Zi中的show()无法覆盖Fu中的show()
static void show()
^
覆盖的方法为 static
1 个错误
问题2.为啥会有以上错误提示?
问题3.假如我把子类的show()改为void show(); 父类改为static void show();
结果为啥还是:D:\延飞>javac ExtendDemo2.java
ExtendDemo2.java:20: 错误: Zi中的show()无法覆盖Fu中的show()
void show()
^
被覆盖的方法为static
1 个错误