I have java.lang.ArrayIndexOutOfBoundsException: 1 >= 0
raised in javax.swing.table.DefaultTableColumnModel.getColumn
Nothing in the stack trace refers to any of the classes that I defined,
this is why I have no clue how to debug it. To further complicate the
issue, the error is not reproduced consistently. Next, there is no
ColumnModel class anywhere in my implementation; the only classes that
I defined  are TreeTable, and TreeTableModel, and sure enough my
TreeTableModel defines more than 0 columns.

P.S. This stuff seems to be designed by dilletants. Check up javadoc;
what is the description of  DefaultTableColumnModel? "Serialized
objects of this class will not be compatible with future Swing
releases" -- a warning that sits there for 10 years already?