jlist установил выбранное значение
JList list = new JList(new String[]{"A","B","C"});
list.setSelectedIndex(0);
// "A" would be selected by default in this example.
snowy
JList list = new JList(new String[]{"A","B","C"});
list.setSelectedIndex(0);
// "A" would be selected by default in this example.