Hi Perm, I'm sorry, my mistake. To see the difference you must run the example with JDK 8, e.g. without your patch. The example contains two fields "jdk8" and "jdk9". The "jdk9" field simulates the behaviour of JTextField with your patch. Both fields "jdk8" and "jdk9" should have the same size on the screen. But after your patch the "jdk9" field is only 10 pixel wide.
Suppose developers had following use case in the past: We need a field which should be 10 columns wide and 20 pixels high. The field must be inside of a panel with BoxLayout and laid out horizontally from left to right. What did they done in such situations: JTextField field = new JTextField(10): field.setPreferredSize(new Dimension(10, 20)); // The real width will be calculated by JTextField using the number of columns. JPanel content = new JPanel(); BoxLayout layout = new BoxLayout(content, BoxLayout.X_AXIS); content.setLayout(layout); content.add(field); This code implements the use case above (from JavaDocs of BoxLayout: BoxLayout attempts to arrange components at their preferred widths (for horizontal layout) or heights (for vertical layout).). But your change would break now this implementation. After your change the field would have only the size of 10 pixels x 20 pixels ant not the expected 10 columns x 20 pixels. Best regards, Andrej Golovnin
