Java

use the following link , which helps you to install or update the missing plugins in the linux.... http://fedoraproject.org/wiki/YumUpgradeFaq

service iptables stop-------> this is used to stop the firewall service iptables start-------> this is used to start the firewall.

se the below link to get idea on the particular concept http://www.cafeconleche.org/books/xmljava/chapters/ch10s03.html

see this link for mysql basic commands.. which is used in the command prompt http://www.pantz.org/software/mysql/mysqlcommands.html