HQL query with LIKE having issues

Parameters inside string literals are not resolved.

You need to add %s to parameter values with string concatenation – either at the program side

String QUERY = "FROM Person as p WHERE p.createUser = : createUser 
     AND p.personId in " +
     "(SELECT pn.personId FROM PersonName pn " + 
     "WHERE pn.personNameType="FIRST" " + 
     "AND pn.name LIKE :firstName)";

(List<Person>)session.createQuery(QUERY)
    .setString("createUser", createUser)
    .setString("firstName", "%" + firstName + "%").list();

or at the database side:

String QUERY = "FROM Person as p WHERE p.createUser = : createUser 
     AND p.personId in " +
     "(SELECT pn.personId FROM PersonName pn " + 
     "WHERE pn.personNameType="FIRST" " + 
     "AND pn.name LIKE CONCAT('%', :firstName, '%'))";

(List<Person>)session.createQuery(QUERY)
    .setString("createUser", createUser)
    .setString("firstName", firstName).list();