No statements may be issued when any streaming result sets are open and in use on a given connection

Noways, i have encountered a problem about mysql and ResultSet.

the Exception Trace:

java.sql.SQLException: Streaming result set com.mysql.jdbc.RowDataDynamic@7834eb is still active. No statements may be issued when any streaming result sets are open and in use on a given connection. Ensure that you have called .close() on any active streaming
result sets before attempting more queries.

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:930)

at com.mysql.jdbc.MysqlIO.checkForOutstandingStreamingData(MysqlIO.java:2646)

at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1861)

at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)

at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2548)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1846)

By default, ResultSets are completely retrieved and stored in memory. In most cases this is the most efficient way to operate, and due to the design of the MySQL network protocol is easier to implement. If you are working with ResultSets that have a large number
of rows or large values, and can not allocate heap space in your JVM for the memory required, you can tell the driver to stream the results back one row at a time.

To enable this functionality, you need to create a Statement instance in the following manner:

stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
stmt.setFetchSize(Integer.MIN_VALUE);

The combination of a forward-only, read-only result set, with a fetch size of 

Integer.MIN_VALUE

 serves
as a signal to the driver to stream result sets row-by-row. After this any result sets created with the statement will be retrieved row-by-row.

There are some caveats with this approach. You will have to read all of the rows in the result set (or close it) before you can issue any other queries on the connection, or an exception will be thrown.
Reference:  http://bugs.mysql.com/bug.php?id=39156

                    http://dev.mysql.com/doc/refman/5.1/en/connector-j-reference-implementation-notes.html