sql> create sequence t_seq;
 
Sequence created.
 
sql> create table t (pk int, name varchar2(30));
 
Table created.
 
sql> create or replace trigger t_trg
  2  before insert on t
  3  for each row
  4  begin
  5    select t_seq.nextval into :new.pk from dual;
  6  end;
  7  /
 
Trigger created.
 
sql> var pk_val number;
sql> set sqlp sql>
sql>insert into t (name) values ('Test') returning pk into :pk_val;
 
1 row created.
 
sql>print pk_val
 
   PK_VAL
---------
        1
 
sql>insert into t (name) values ('Second') returning pk into :pk_val;
 
1 row created.
 
sql>print pk_val
 
   PK_VAL
---------
        2

CallableStatement cs =
  conn.prepareCall("begin insert into t (name) values (?) returning pk_column into ?; end;");