The developers certification requires you to develop a working solution to a problem clearly defined (albeit with a couple of bad definitions). So you have to:
Create Java classes that will provide basic CRUD operations on a flat file provided to youCreate Java classes to provide multi-user capabilities for your simple databaseCreate client and server classes so that your database can be connected to over a network in multi-user mode with proper locking and data integrity ensuredCreate a standalone GUI that will connect to your database in both standalone mode and in networked mode (although not simultaneously) and update recordsSubmit the source code and documentation to an assessor for marking
The second part of the exam is answering some questions on the assignment so that the assessor can verify that you were the person who created your submission.
The architects certification is completely different.
Part one is similar to the
SCJP in that it is generally multi-choice questions, but the questions are at a much higher level, and are best answered by people who have experience in the field. So you might get a question about which technology is best in a particular scenario, where there are 2 or 3 answers that could be right - all of them will work for the given scenario - but you are expected to know that for the question provided one answer is preferable to another. The breadth of questions is much greater than SCJP as well - rather than knowing just one set of APIs, an architect is expected to know the capabilities of a large number of systems.
Part 2 is an assignment that must be submitted and will be graded for correctness. You will be asked to design a system for a small company, and along the way you will have to:
Determine, based on really loosely defined criteria, how you are going to solve the problems provided (e.g. how do you connect your Java systems to legacy systems)create UML diagrams (class / deployment / sequence / ...) based on descriptions of existing systems and existing UML diagramscreate descriptions of what your major design decisions were, and what major non-functional requirements you identified (and hopefully mitigated).
The third part of the exam is answering some questions on the assignment so that the assessor can verify that you were the person who created your submission.
As with part one, there is no one "right answer" - there are multiple ways that any given problem can be solved. However, like part one, there are good solutions, mediocre solutions, and bad solutions. This is where the experience comes into play - if you have 10 to 20 years as a developer / technical lead / architect, you will probably automatically head towards the great answers. If you are still in school you may not even understand what the differences are (or worse, may not even realize that there are choices to be made).