Index: src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java =================================================================== --- src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java (revision 493699) +++ src/main/java/common/javax/swing/plaf/basic/BasicComboBoxUI.java (working copy) @@ -79,10 +79,16 @@ } public Dimension preferredLayoutSize(final Container parent) { + if (parent == null) { + throw new NullPointerException("parent is null"); + } return new Dimension(0, 0); } public Dimension minimumLayoutSize(final Container parent) { + if (parent == null) { + throw new NullPointerException("parent is null"); + } return new Dimension(0, 0); }