When CVS updates, it automatically performs a merge, that is, it combines repository changes with your workspace changes. This synchronizes your workspace with the repository. All changes are preserved. If there are textual conflicts, they are flagged to be reconciled by the user.
Note that CVS only recognizes textual conflicts, not logical ones.
To learn how to reconcile merge conflicts, see the "CVS Update (Merge) File" topic in "Team development using JBuilder."