Question

I want to receive a List as input, Java is showing me no error in:

List<String> A;
 ObjectOutputStream ins = new ObjectOutputStream(soc.getOutputStream());
  ins.writeObject(A);

The above code executes without error, however this doesn’t:

List<String> ls;
    ObjectInputStream in = new ObjectInputStream(soc.getInputStream());
       in.readObject(ls);

If I can send a List<>, why cant I accept it? Any reasons and suggestions for the output code?

Answer 1

readObject doesn’t take any parameters. You want:

List<String> list = (List<String>) in.readObject();

(Of course, this isn’t really type-safe, and the compiler should at least raise warnings. How you deal with that is a separate matter.)