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  1. JDK
  2. JDK-4361751

JDesktopIcon.get(Maximum)MinimumSize() methods throw NPE in Metal L&F

    Details

    • Subcomponent:
    • Resolved In Build:
      beta
    • CPU:
      sparc
    • OS:
      solaris_2.6

      Description



      Name: nkR10003 Date: 08/11/2000


      JDesktopIcon.get(Maximum)MinimumSize() methods throw NullPointerException.
      JavaDoc comments for JComponent.getMinimumSize() state: "If the minimum size has been set to
      a non-null value just returns it. If the UI delegate's getMinimumSize() method returns a
                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      non-null value then return that;" So UI delegate's getMinimumSize() should be invoked in case
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      minimum size has not been set. If Metal UI delegate has been installed
      MetalDesktopIconUI.getMinimumSize(JComponent) throws NullPointerException. This happens
      because of invalid overloading installComponents method in MetalDesktopIconUI class. This
      method does not call super.installComponents() and therefore does not initialize components
      which are necessary for apropriate functioning of _inherited_ methods (get(Maximum)MinimumSize
      just the case).

      See piece of code source below:

      //BasicDesktopIconUI

      protected void installComponents() {
          ............
          iconPane = new BasicInternalFrameTitlePane(frame);
          ............
      }

      public Dimension getMinimumSize(JComponent c) {
          return iconPane.getMinimumSize();
      }

      public Dimension getMaximumSize(JComponent c){
          return iconPane.getMaximumSize();
      }

      //MetalDesktopIconUI

      1. installComponents method is overloaded in the class
      2. nothing about iconPane field in the class
      3. no super.installComponents() call in the class
      4. get(Maximum)MinimumSize methods are not overloaded

      Example below demonstrates this problem:
      ------------------example--------------------
      //test.java
      import javax.swing.*;
      class test {
          public static void main(String[] args) {
              JInternalFrame.JDesktopIcon icon =
                  new JInternalFrame.JDesktopIcon(new JInternalFrame());
              System.out.println("icon.getUI: " +
                      icon.getUI());
              System.out.println("icon.getMinimumSize: " +
                      icon.getMinimumSize());
              System.out.println("icon.getUI().getMinimumSize: " +
                      icon.getUI().getMinimumSize(icon));
              System.out.println("Passed: OKAY");
              System.exit(0);
          }
      }
      ----------------output:----------------------
      icon.getUI: javax.swing.plaf.metal.MetalDesktopIconUI@482923
      Exception in thread "main" java.lang.NullPointerException
              at javax.swing.plaf.basic.BasicDesktopIconUI.getMinimumSize(BasicDesktopIconUI.java:115)
              at javax.swing.JComponent.getMinimumSize(JComponent.java:1130)
              at test.main(test.java:7)
      ---------------------------------------------
      ======================================================================

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            • Assignee:
              joutwatesunw Joshua Outwater (Inactive)
              Reporter:
              knasunw Kna Kna (Inactive)
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              • Created:
                Updated:
                Resolved:
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