Cafe is Symantecs' visual environment for developing Java applications and applets. When the book was published, Cafe was already on version 1.3, whereas it deals with version 1.2. Back then the differences made no real odds. However, Cafe has now progressed onto version 3. As a result the changes are more marked. However, the basics of Java that the books deals with have not changed, provided you are still using Java 1.x, rather than having migrated onto Java 2.
With all this in mind, the book is fine for learning the basics of Java, covering all of the expected ground. Cafe as a visual environment is much easier to code Java in than say using Sun's (free) command line tools, and the book does try and help the reader appreciate the advantages of this. As with all of these "in 21 days" books, there are the usual reservations in artificially forcing the chapters in 21 'chunks'. Nevertheless, each of these can be done in around an hour--a good structured way to learn.
With Cafe and Java having developed so much over the last couple of years, this a book to look for in the cut-price section for the Java knowledge, or to use with one of the computer magazine etc. free give-aways CDROMS of Cafe. Otherwise, you should be looking at a more up to date reference book covering Java 2.