<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
    <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
    <property name="hibernate.connection.url">jdbc:postgresql://localhost/pgtest</property>
    <property name="hibernate.connection.username">pgtest</property>
    <property name="hibernate.connection.password">pgtest</property>
    <property name="hibernate.show_sql">true</property>
    <mapping resource="pgtest/Pgtest.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

postgres=# create database pgtest;
CREATE DATABASE
postgres=# \c pgtest
You are now connected to database "pgtest".
pgtest=# CREATE SEQUENCE pgtest_seq;
CREATE SEQUENCE
pgtest=# CREATE TABLE pgtest(id integer not null primary key default nextval('pgtest_seq'), test varchar(50));
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "pgtest_pkey" for table "pgtest"
CREATE TABLE
pgtest=# insert into pgtest(test) values('test #1');
INSERT 0 1
pgtest=# SELECT * from pgtest;
id |  test
----+---------
  1 | test #1
(1 row)

pgtest=# CREATE USER pgtest with password 'pgtest';
CREATE ROLE
pgtest=# grant all privileges on pgtest to pgtest with grant option;
GRANT
pgtest=# grant all privileges on pgtest_seq to pgtest with grant option;
GRANT

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2009.02.19 15:23:31 by Hibernate Tools 3.2.1.GA -->
<hibernate-mapping>
    <class name="pgtest.Pgtest" table="pgtest" schema="public">
        <id name="id" type="int">
            <column name="id" />
            <generator class="assigned" />
        </id>
        <property name="test" type="string">
            <column name="test" length="50" />
        </property>
    </class>
</hibernate-mapping>

Pgtest t = (Pgtest) session.load(Pgtest.class, 1);
System.out.println("pgtest(#1).test: " + t.getTest());

SQLQuery sql = session.createSQLQuery("insert into pgtest(test) values(?)");
sql.setString(0, "test #2");
System.out.println("sql: " + sql.getQueryString().toString());
System.out.println("result: " + sql.executeUpdate());

session.flush();

Hibernate: select pgtest0_.id as id0_0_, pgtest0_.test as test0_0_ from public.pgtest pgtest0_ where pgtest0_.id=?
pgtest(#1).test: test #1
sql: insert into pgtest(test) values(?)
Hibernate: insert into pgtest(test) values(?)
result: 1

Hibernate: select pgtest0_.id as id0_0_, pgtest0_.test as test0_0_ from public.pgtest pgtest0_ where pgtest0_.id=?
Hibernate: insert into pgtest(test) values(?)

Class.forName("org.postgresql.Driver");
String url = "jdbc:postgresql://localhost/pgtest?user=pgtest&password=pgtest";
Connection conn = DriverManager.getConnection(url);

Statement in = conn.createStatement();
in.execute("insert into pgtest(test) values('test #3')");
in.close();

Statement st = conn.createStatement();
ResultSet rs = st.executeQuery("SELECT * FROM pgtest");
while (rs.next()) {
System.out.println("ID "+rs.getString(1)+": "+rs.getString(2));
}
rs.close();
st.close();

Session session = HibernateUtil.getSessionFactory().openSession();
Transaction tx = session.beginTransaction();
tx.begin();

Pgtest t2 = new Pgtest();
t2.setTest("test #3");
session.save(t2);

tx.commit();
session.close();