Index: src/main/java/common/javax/swing/plaf/basic/BasicProgressBarUI.java =================================================================== --- src/main/java/common/javax/swing/plaf/basic/BasicProgressBarUI.java (revision 494496) +++ src/main/java/common/javax/swing/plaf/basic/BasicProgressBarUI.java (working copy) @@ -333,6 +333,9 @@ } protected void setAnimationIndex(final int newValue) { + if (progressBar == null) { + throw new NullPointerException("progressBar is null"); + } animationIndex = newValue % maxAnimationIndex; }