I get a communication link failure while application tries to establish a connection with DB.

[#|2010-04-08T20:09:57.825+0300|SEVERE|glassfish3.0|javax.enterprise.system.std.com.sun.enterprise.v3.services.impl|_ThreadID=24;_ThreadName=Thread-1;|Cannot connect to database server = com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.|#]

Precisely at this string:

Statement s = conn.createStatement();

where conn is defined as follows:

private static java.sql.Connection conn;

For this app I have set a connection pool with default parameters and currently it (app) uses both JPA and direct JDBC queries. Recreation of connection pool gave nothing, connection pool ping gave next message:

Ping Connection Pool for pool is Failed. Ping failed Exce
ption - Connection could not be allocated because: Communications lin
k failure%%%EOL%%%%%%EOL%%%The last packet sent successfully to the s
erver was 0 milliseconds ago. The driver has not received any packets
from the server. Please check the server.log for more details.%%%EOL
%%%Ping failed Exception - Connection could not be allocated because:
Communications link failure

and flushing the connection pool gave:

com.sun.enterprise.admin.cli.CommandException: remote failure: Failed to flush connection pool ...

However I can connect to the database from a terminal. Besides I have the same app working on my local machine with identical connection pool settings.

Any one has an idea on whats going on or how to solve the trouble?