If the print-function is not enough for you, then you can use the logger Object to log Commands, information warnings and more.

You can access the Formatting Handler using the logger global keyword.

• logCommand(String message);
• logInfo(String message);
• logWarning(String message);
• logError(String message);

• logError(String message, Throwable exception);
• logPlayer(IPlayer player);

You can not use Java's throwables so the first Method is useless.
The second Method does absolutely nothing. Literally, the implementation is empty!