This PR fixes a bunch of NPEs when a null `SelectionModel` or `FocusModel` is set on a `ListView`.
The following NPEs are fixed (all are also covered by exactly one test case): NPEs with null selection model: - Mouse click on a `ListCell` - SPACE key press - KP_UP (arrow up) key press - HOME key press - END key press - BACK_SLASH + CTRL key press NPEs with null focus model: - SPACE key press - Select an items: getSelectionModel().select(1) - Clear-Select an item and add one after: listView.getSelectionModel().clearAndSelect(1); listView.getItems().add("3"); ------------- Commit messages: - 8279640: ListView with null SelectionModel/FocusModel throws NPE Changes: https://git.openjdk.java.net/jfx/pull/711/files Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=711&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8279640 Stats: 145 lines in 4 files changed: 130 ins; 2 del; 13 mod Patch: https://git.openjdk.java.net/jfx/pull/711.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/711/head:pull/711 PR: https://git.openjdk.java.net/jfx/pull/711