Connection pooling in java

hi all..

i am tring to use connection pool with postgresql..but it give an Exception when it is going to execute the line following. InitialContext().rebind("DataSource", source)


the cord is as follow.



Jdbc3PoolingDataSource source = new Jdbc3PoolingDataSource();
source.setDataSourceName("A Data Source");
source.setServerName("localhost");
source.setDatabaseName("mmsc");
source.setUser("janaka");
source.setPassword("1234");
source.setMaxConnections(10);
    try {
      new InitialContext().rebind("DataSource", source);
    }
    catch (NamingException ex) {
      System.out.println(ex.getMessage());
      ex.printStackTrace(); 
    }




the given exception is as follow....


javax.naming.NoInitialContextException : Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file:  java.naming.factory.initial
    at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java :645)
    at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:247)
    at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:284)
    at javax.naming.InitialContext.rebind(InitialContext.java :367)
    at MainClass.main(MainClass.java:29)



please help me to solve this..








--
...........Janaka Priyadarshana...........