Split 1 column into 3 columns in spark Java

Question

I have a dataframe in Spark using Java that has a column that I need split.

test.show()

+-------------+
|columnToSplit|
+-------------+
|        a.b.c|
|        d.e.f|
+-------------+

I need this column split out to look like this:

+--------------+
|col1|col2|col3|
|   a|   b|   c|
|   d|   e|   f|
+--------------+