Index: src/main/java/common/javax/swing/JLayeredPane.java =================================================================== --- src/main/java/common/javax/swing/JLayeredPane.java (revision 490282) +++ src/main/java/common/javax/swing/JLayeredPane.java (working copy) @@ -255,6 +255,10 @@ * @param position the position to set */ public void setPosition(final Component c, final int position) { + if (c == null) { + throw new NullPointerException(); + } + int layer = getLayer(c); int index = getIndexOf(c); if (index == -1) {