seems like the suggestion here is the fix but i'm not super familiar with java

stmt.SetNull(i,Types.NULL)

also found this

Let's assume you have an Object with a null value in your application:
Object obj = null ;
The error message is indicating that your application cannot use the PreparedStatement.setObject(int,Object) method to bind the null value:
PreparedStatement ps = con.prepareStatement ... ;
ps.setObject(1, obj) ; // will throw exception if obj is null
Instead, your application must specify the data type of the null value using one or the other of these methods:
ps.setObject(1, obj, Types.VARCHAR) ; // or some other java.sql.Types constant
// or
ps.setNull(1, Types.VARCHAR) ; // or some other java.sql.Types constant
The Teradata Database requires the data type to be specified for a NULL value, so the Teradata JDBC Driver, in turn, must require the application to specify the java.sql.Types constant for a null value.