Java convention

In "Learning to Program with Alice" pgs. 9, 12, 13... and in the Alice program itself "world" is displayed with a lowercase initial letter, but on page 15 "world" is changed to an initial capital letter. I'm presuming World is indicative of a class. Are there directives that indicate changing to a capital letter once a new world is created to be more inline with the usual Java convention to capitalize the name of a class? Will Alice do this automatically and I'm not setting a preference?
Pardon me if this is too elementary a question. I'm new to Alice and still learning Java.
Thank you.