I see from this thread how I can set the "Required" (NOT NULL) property on an existing column. However, if I try to do that while creating the table ...
new TableBuilder("Table1")
.addColumn(new ColumnBuilder("id", DataType.LONG)
.setAutoNumber(true))
.addColumn(new ColumnBuilder("txt", DataType.TEXT)
.setLengthInUnits(50)
.putProperty(PropertyMap.REQUIRED_PROP, true))
.addIndex(new IndexBuilder(IndexBuilder.PRIMARY_KEY_NAME)
.addColumns("id").setPrimaryKey())
.toTable(db);
... I wind up with a table that Microsoft Access cannot manipulate. I can open the database itself, but as soon as I try to work with the table I get the error

Cannot open database ''. It may not be a database that your application recognizes, or the file may be corrupt.
If I simply omit the .putProperty call ...
new TableBuilder("Table1")
.addColumn(new ColumnBuilder("id", DataType.LONG)
.setAutoNumber(true))
.addColumn(new ColumnBuilder("txt", DataType.TEXT)
.setLengthInUnits(50))
.addIndex(new IndexBuilder(IndexBuilder.PRIMARY_KEY_NAME)
.addColumns("id").setPrimaryKey())
.toTable(db);
... then the resulting table is accessible.
A bit of poking around seems to suggest that it might be related to a Property being created whose name is an empty string, but it's tricky to investigate using the tools at my disposal because Jackcess Column#getProperties seems to think that the column has none, and MSACCESS won't work with the table at all.
alright, think i figired it out. access doesn't like the "empty" property map for the table.
Fixed in trunk, will be in the 2.1.9 release.