A11Y implementation on macOS has to directly call the 'JList.setSelectedIndex' method in order to request selection on an item (see 'CAccessibility.requestSelection'). The reason is that a11y API lacks appropriate method.There's only 'javax.accessibility.AccessibleSelection#addAccessibleSelection' which is mapped to 'javax.swing.JList#addSelectionInterval', it can not be used to set selected index.