... Note that the size of the returned array may be greater than the number of slices currently in the stack, with unused elements set to null. public int getSize () . Returns the number of slices in this stack. public java.lang.String[] getSliceLabels () . ... Returns null if the stack is empty or the label of the first slice is null. public java.lang.String getSliceLabel (int n) . ... Returns null if the slice does not have a label. public void setSliceLabel (java.lang.String label, int n) . ...