Ask a LIST of things-CodePudding

Public class aa {

Private String aa;
Private String bb;

Private List The List;

The get...
The set...
}

Public class cc {

Private String c1;
Private String c2.

The get...
The set...
}

Public class dd {

Public string aaaa {

Aa name=new (aa);

Aa. Getlist (). The add (new cc (' 1 ', '2'))
}

}

Aa. Getlist (). The add (new cc (' 1 ', '2'))
Now the problem is, I use getlist. Add it to this list add object, he has been an error, Create breakpoint: null

But I use the

LIST Bb=new ArrayList<> (a);

Aa. SetLIST (bb);

So that it can be normal assignment? Why?

Where is write wrong, getlist (). The add () should not also can?