The base class for the Scalar UDFs. All the scalar UDF classes needs to extend this and implement a method named
"execute". The number and type of arguments for the execute method in the UDF class should match the number and type of fields
used while invoking this UDF in SQL statement.
Say for e.g. User creates a UDF class with signature int execute(int var1, String var2). It can be used in a SQL query
select myudf(id, name) from profile
In the above query, Profile should contain fields named 'id' of INTEGER/NUMBER type and 'name' of type VARCHAR/CHARACTER