Java接口作为类型使用

[java]代码库

public class Test {
public void test1(A a){
a.doSth();
}
public static void main(String[] args) {
Test t = new Test();
A a = new B();
t.test1(a);
}
}
interface A{
public int doSth();
}
class B implements A{
@Override
      
      
public int doSth() {
System.out.println("now in B");
return 123;
}
}//源代码片段来自云代码http://yuncode.net
			


public class Test {
public void test1(A a){
a.doSth();
}
public static void main(String[] args) {
Test t = new Test();
A a = new B();
t.test1(a);
}
}
interface A{
public int doSth();
}
class B implements A{
@Override
      
      
public int doSth() {
System.out.println("now in B");
return 123;
}
}//源代码片段来自云代码http://yuncode.net