today I found a error on my squirrel-sql software when I was trying to access to my localhost database using com.jdbc.mysql.Driver.
The problem came up using the following message:
"...com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure ...."""
After a really long research, doing on other many similar software, re-setting each configuration files on my computer (ArchLinux), at the end I've figured out how that error came and how we could solve it.
To check whether your problem has the same reasons that mine was, execute the following line, when mysqld service is still running:
Input: $ sudo nmap -p 3306 localhost
PORT STATE SERVICE
3306/tcp close mysql
If this is your case, that has a easy resolution, just you should comment the following line on your my.cnf file:
And the the output for last command will be:
PORT STATE SERVICE3306/tcp open mysql
PROBLEM SOLVED !!!