具有通配符的通用数组导致错误

Question

i wanted to create JComboBox´s with Type String, but having it in an array, so i used wildcard for the array and String for the single elements:

JComboBox<?>[] combos=new JComboBox<?>[10];
...
combos[i]=new JComboBox<String>();

same with DefaultComboBoxModels:

DefaultComboBoxModel<?>[] comboModels=new DefaultComboBoxModel<?>[10];
...
comboModels[i]=new DefaultComboBoxModel<String>();

assigning them to each other:

...
combos[i].setModel(comboModels[i]);

now gives compiler error (capture#13-of ? not applicable to capture#14-of ?). would have expected that the single elements are set to String and everything´s fine. what´s that about, how to deal with it? (except of doing it raw)

Answer 1

Java needs to ensure, that model and combo are of the same type. On the given example, once types are gone after erasure, there is no way to do this. You could as well set model<Integer> to combo<String> with such way.