I would like to know if it is possible to activate code for a specific player. I know it will have to be an 'if...then' statement, although I don't know exactly how to make it check the player's name. Anyone know how?

if(player.getDisplayName() == "TARGET") {
//stuff
}

When comparing Strings, it's best to use the string1.equals(string2) method, as == will check identity rather than compare the actual String contents.

 

if (player.getCommandSenderName().equals("target_name")) {
// code
}