Communications link failure (MySQL)

When you find this exception:

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The cause is that you cannot to MySQL server. Simply, try:

telnet 127.0.0.1 3306

in order to verify that it does not work.

My problem is that I bind MySQL server to a specific address.

I fix it by binding MySQL server to 0.0.0.0 (all network interface).