You did not overwrite ArrayList.add(Object). Dog is an Object, so...
Solution
1. add
public void add(Object o) {
if( !(o instanceof Cat) )
...
else
...
}or:
2. change
class Cats {
Arraylist list = new Arraylist;
public void add(Cat cat) {
...
}
}
Solution
1. add
public void add(Object o) {
if( !(o instanceof Cat) )
...
else
...
}or:
2. change
class Cats {
Arraylist list = new Arraylist;
public void add(Cat cat) {
...
}
}
解决方案 »
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