Ideal model for accesing data

Question

i'm trying to transfer some data (about 100,000 rows) to mysql database. i already has my Data Access Object(DAO), so i reuse it. when my DAO add about 500 rows, this exception occurs:
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION **
java.net.SocketException
MESSAGE: java.net.BindException: Address already in use: connect
STACKTRACE:
java.net.SocketException: java.net.BindException: Address already in use: connect
        at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:151)
        at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:280)
        at com.mysql.jdbc.Connection.createNewIO(Connection.java:1691)
        at com.mysql.jdbc.Connection.<init>(Connection.java:405)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)
        at java.sql.DriverManager.getConnection(DriverManager.java:512)
        at java.sql.DriverManager.getConnection(DriverManager.java:171)
        at trade.connector.ConnectionProvider.getConnection(ConnectionProvider.java:71)
        at trade.access.LoginValidator.validate(LoginValidator.java:29)
        at trade.access.UserAccess.getUser(UserAccess.java:124)
        at trade.access.UserAccess.addUser(UserAccess.java:162)
        at trade.access.UserAccess.main(UserAccess.java:254)
** END NESTED EXCEPTION **
        at com.mysql.jdbc.Connection.createNewIO(Connection.java:1754)
        at com.mysql.jdbc.Connection.<init>(Connection.java:405)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)
        at java.sql.DriverManager.getConnection(DriverManager.java:512)
        at java.sql.DriverManager.getConnection(DriverManager.java:171)
        at trade.connector.ConnectionProvider.getConnection(ConnectionProvider.java:71)
        at trade.access.LoginValidator.validate(LoginValidator.java:29)
        at trade.access.UserAccess.getUser(UserAccess.java:124)
        at trade.access.UserAccess.addUser(UserAccess.java:162)
        at trade.access.UserAccess.main(UserAccess.java:254)
Exception in thread "main" i retry transfering but this exception occurs again and again. if i retry after about 1 minute, it can resume transfering about 500 rows again.
Is this problem cause by database protection from network flood attack? i use single shot connection method (connect when needed, and disconnect when job done). so if add method need 2 query (2 times connect), it takes about 1000 re-connection.
i change connection from single shot connection to connection pooling. the problem still occurs... so i assume the protection apply for statement (i recreate statement for about 1000 times). finally i write extra code for transfering. reuse statement (Prepared Statement),not close and recreate and problem solve.
So what 'ideal model' for DAO (logical layer)? for every access method, we create Statement, use it, and close it. this will cause database server block our connection when using this method repeatly (over 1000 times). if we leave the statement open, it will cost network traffic to keep it alive and we often use only a part accesing method, not all.

Answer 1

you are right malcolmmc. i'm running out of local port. i check with netstat & here is the output:
  TCP    TOSHIBA2450:3306       localhost:3987         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3988         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3989         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3990         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3991         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3992         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3993         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3994         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3995         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3996         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3997         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3998         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:3999         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4000         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4001         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4002         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4003         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4004         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4005         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4006         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4007         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4008         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4009         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4010         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4011         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4012         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4013         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4014         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4015         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4016         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4017         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4018         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4020         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4021         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4022         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4023         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4024         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4025         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4026         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4027         TIME_WAIT
  TCP    TOSHIBA2450:3306       localhost:4028         TIME_WAITi already try to change my code to use only one connection. and the result is same. i assume create statement will create a new connection. i mean althought i'm not re-creating java.sql.Connection, but when i create java.sql.Statement, it will create new TCP/IP Connection. but i do call:
preparedstatement.close();
pool.returnConnection(con); // con.close();i wonder how to close this connection (tcp/ip)...