On Fri, 24 May 2024 05:03:07 GMT, Prasanta Sadhukhan <[email protected]> wrote:
> Issue is observed in JTable demo in SwingSet2 whereby if we set the focus on > a table cell (or click on a table cell) and Press Ctrl+F1 (show/hide tooltip) > on a cell of JTable then NullpointerException is seen > >> Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: >> Cannot invoke "java.awt.event.MouseEvent.getLocationOnScreen()" because >> "this.mouseEvent" is null > > This is because ToolTip associated with JTable demo button at top of > SwingSet2 has MouseMotion Listener which causes [mouseEvent to be > null](https://github.com/openjdk/jdk/blame/da3001daf79bf943d6194d9fd60250d519b9680d/src/java.desktop/share/classes/javax/swing/ToolTipManager.java#L573) > when mouse exits the demo button area and enter the table cells area where > show/hide tooltip causes showTipWindow to be called trying to access > `mouseEvent` which is null. > Fix is made to check for null in this kind of cases..No regression test is > added as it can be checked easily with SwingSet2.. src/java.desktop/share/classes/javax/swing/ToolTipManager.java line 273: > 271: GraphicsConfiguration gc = getDrawingGC(toFind); > 272: if (gc == null) { > 273: if (mouseEvent != null) { In the same method **showTipWindow**, mouseEvent's _getLocationOnScreen_ method is accessed at [L268](https://github.com/openjdk/jdk/blame/da3001daf79bf943d6194d9fd60250d519b9680d/src/java.desktop/share/classes/javax/swing/ToolTipManager.java#L268C13-L268C13) and mouseEvent's _getX_ and _getY_ methods are accessed at [L304](https://github.com/openjdk/jdk/blame/da3001daf79bf943d6194d9fd60250d519b9680d/src/java.desktop/share/classes/javax/swing/ToolTipManager.java#L304), guess we should guard them as well with null check. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/19379#discussion_r1615784054
