一道关于Java的题(来自SCJP)Which Man class properly represents the relationship "Man has a best friend who is a Dog"?(下面哪个关于Man的类准确反映了这个关系:“狗是人类最好的朋友”?)A. class Man extends Dog
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![一道关于Java的题(来自SCJP)Which Man class properly represents the relationship](/uploads/image/z/13773151-55-1.jpg?t=%E4%B8%80%E9%81%93%E5%85%B3%E4%BA%8EJava%E7%9A%84%E9%A2%98%EF%BC%88%E6%9D%A5%E8%87%AASCJP%EF%BC%89Which+Man+class+properly+represents+the+relationship+%22Man+has+a+best+friend+who+is+a+Dog%22%3F%EF%BC%88%E4%B8%8B%E9%9D%A2%E5%93%AA%E4%B8%AA%E5%85%B3%E4%BA%8EMan%E7%9A%84%E7%B1%BB%E5%87%86%E7%A1%AE%E5%8F%8D%E6%98%A0%E4%BA%86%E8%BF%99%E4%B8%AA%E5%85%B3%E7%B3%BB%EF%BC%9A%E2%80%9C%E7%8B%97%E6%98%AF%E4%BA%BA%E7%B1%BB%E6%9C%80%E5%A5%BD%E7%9A%84%E6%9C%8B%E5%8F%8B%E2%80%9D%3F%EF%BC%89A.+class+Man+extends+Dog)
一道关于Java的题(来自SCJP)Which Man class properly represents the relationship "Man has a best friend who is a Dog"?(下面哪个关于Man的类准确反映了这个关系:“狗是人类最好的朋友”?)A. class Man extends Dog
一道关于Java的题(来自SCJP)
Which Man class properly represents the relationship "Man has a best friend who is a Dog"?
(下面哪个关于Man的类准确反映了这个关系:“狗是人类最好的朋友”?)
A. class Man extends Dog { }
B. class Man implements Dog { }
C. class Man { private BestFriend dog; }
D. class Man { private Dog bestFriend; }
E. class Man { private Dog; }
F. class Man { private BestFriend; }
参考答案给的是D,可我觉得C更准确一些.另外E、F中的尖括号是什么意思.求达人指点
一道关于Java的题(来自SCJP)Which Man class properly represents the relationship "Man has a best friend who is a Dog"?(下面哪个关于Man的类准确反映了这个关系:“狗是人类最好的朋友”?)A. class Man extends Dog
D比C更准确.
DOG是一个实体,定义为一个类很正确,BestFriend只是一种形容,做为一个类没有什么属性可定义,所以只适合用来做为对象的命名
Man私有的一只名为最好的朋友的Dog
private Dog bestFriend;
尖括号属于泛形的知识,但这里的语法是错的,尖括号只能是跟在集合后面的,比如
private List dogs;
限制这个list集合中的对象只能是Dog类的对象