When creating your character in Star Wars Galaxies, there are 9 professions (classes) to choose from. They are Jedi, Commando, Spy, Medic, Bounty Hunter, Smuggler, Officer, Trader, and Entertainer. The Trader profession is sub divided into four concentrations: Munitions, Domestic, Structures, and Engineer.
After creating a character, you may change your character's profession at any time by visiting a profession counselor NPC. The first profession change, called a respec, will be free, but the credit cost increases each time you do it.
When your character reaches level 10, his profession can be customized a bit further with the use of the expertise system.
List of Combat Professions
Of the 9 starting professions, 7 of them are combat oriented. Many would consider these professions to be the "main game" as they involve traditional MMO activities such as questing, raiding, PVP, etc.
List of Non-Combat Professions
Star Wars Galaxies is one of the few MMOs that offers player classes that are entirely dedicated to something that isn't combat. While they don't pack much of a punch, these professions are considered extremely useful to the community and can a lot of times make the player a lot of credits!