About Question enthuware.ocpjp.v8.3.1858 :

[rvichith]

A Consumer<T> has the following method signature, void accept(T t). Whereas a List.add has the following, boolean add(E e). The add method returns a boolean whereas the accept method does not. Then how can we use List.add in place of Consumer.accept?

[admin]

Remember that method signature includes only method name and parameter type list. It does not include return type. So, the fact that the add method returns a boolean is irrelevant.
That is why a Consumer instance can be easily implemented using list.add. Something like this:

Code: Select all

class C implements Consumer{
   void accept(T t){
       list.add(t); //the value returned by this call is ignored.
   } 
}

[rvichith]

Thanks admin!