Sun does call SCJA an "entry certification," but it is not "the" entry point. In particular, the SCJA exam is not required for the SCJP exam, which has no exam prerequisites. As for choosing one over the other, you might be interested in this thread.
Also see Sun's Java Certification page for more details. [ June 29, 2006: Message edited by: marc weber ]
"We're kind of on the level of crossword puzzle writers... And no one ever goes to them and gives them an award." ~Joe Strummer sscce.org