Implementations and Collections

Question

Why does this not work...

public ArrayList getEdges() {

return A;

//A is an Arraylist of type \'Action\'. Action implements Ed         


        

Answer 1

Because the generic type must always be the same, not something that extends from it you can rewrite like this for it to work:

public ArrayList getEdges() {

return A;

//A is an Arraylist of type 'Action'. Action implements Edge.

}