hibernate.dialect=org.hibernate.dialect.Oracle9Dialect
hibernate.connection.driver_class=oracle.jdbc.OracleDriver

#hibernate.connection.pool_size= 3 

hibernate.c3p0.minPoolSize= 3 
hibernate.c3p0.maxPoolSize= 10 

 import  java.util.Timer;
 import  java.util.TimerTask;

 public   class  Timeout
   extends  Timer {

   public  Timeout( int  delay,  final  String msg) {
     super (true); // Daemon thread
    schedule(
       new  TimerTask() {
         public   void  run() {
          System.out.println(msg);
          System.exit( 0 );
        }
      }, delay
    );
  }
}

 import  org.hibernate.Session;
 import  org.hibernate.SessionFactory;
 import  org.hibernate.cfg.Configuration;

 import  java.sql.Connection;
 import  java.sql.ResultSet;
 import  java.sql.SQLException;
 import  java.sql.Statement;

 public   class  TestHibernatePool {

   public   static  Session session;

   public   static   void  main(String[] args)
     throws  Exception {

    SessionFactory sessionFactory =  new  Configuration().configure().buildSessionFactory();
    session = sessionFactory.openSession();

     new  SQL("A",  5 ).start();
     new  SQL("B",  5 ).start();
     new  Timeout( 1000 , "Terminated");

  }

}

 class  SQL
   extends  Thread {

   private  String name;

   private   int  counter =  10 ;

   public  SQL(String name,  int  counter) {
     this .name = name;
     this .counter = counter;
  }

   public   void  run() {
     for  ( int  i =  0 ; i < counter; i++) {
      Connection con = TestHibernatePool.session.connection();
      System.out.println(name + " : " + con);
      Statement st =  null ;
      ResultSet rs =  null ;
       try  {
        st = con.createStatement();
        rs = st.executeQuery("select sys_context('userenv', 'sessionid') audsid from dual");
         if  (rs.next()) {
          System.out.println(name + " : " + rs.getString("audsid"));
        }
      }  catch  (SQLException e) {
        System.out.println("SQLException\n" + e.toString());
      }  finally  {
         if  (rs !=  null ) { try  {rs.close();}  catch  (SQLException e) {}}
         if  (st !=  null ) { try  {st.close();}  catch  (SQLException e) {}}
//        if (con != null) {con.close();}
      }
    }
  }
}

A : oracle.jdbc.driver.T4CConnection@140984b
B : oracle.jdbc.driver.T4CConnection@140984b
B : 14087
A : 14087
A : oracle.jdbc.driver.T4CConnection@140984b
A : 14087
A : oracle.jdbc.driver.T4CConnection@140984b
B : oracle.jdbc.driver.T4CConnection@140984b
A : 14087
A : oracle.jdbc.driver.T4CConnection@140984b
A : 14087
B : 14087
A : oracle.jdbc.driver.T4CConnection@140984b
B : oracle.jdbc.driver.T4CConnection@140984b
A : 14087
B : 14087
B : oracle.jdbc.driver.T4CConnection@140984b
B : 14087
B : oracle.jdbc.driver.T4CConnection@140984b
B : 14087