I need to achieve a query like this below.

select * from example where ( a ) or ( b or c or d)

Here a,b,c,d are expressions.

Criteria criteria = session.createCriteria(Example.class);
criteria.add(Restrictions.sqlRestriction("where (a)"));

This is the criteria what i get, which i can't change.
(b or c or d) this can achieved using disjunction.

Disjunction disjunction = Restrictions.disjunction();
disjunction.add(b).add(c).add(d).

But if i add this disjunction to the criteria , it adds AND. i,e select * from example where ( a ) and ( b or c or d). which is not my requirement
criteria.add(disjunction);

Could you please help me on how to add disjunction to sql restriciton with OR condition?

Try

Disjunction disjunction = Restrictions.disjunction();
disjunction.add(b).add(c).add(d)
criteria.add(Restrictions.or(
Restrictions.sqlRestriction(a),
disjunction
));