http://www.developer.com/java/other/article.php/3527736/Java-2-Certifications-An-Introduction.htm
Sun Microsystems' Java 2 Platform is a familiar set of tools known to most in the development world. The Java 2 Platform, Standard Edition (known as J2SE) offers the tools, compilers, APIs, and runtimes for creating and deploying Java applets and applications. The Java 2 Platform, Enterprise Edition (known as J2EE) offers the tools and infrastructure to manage and support Web services that come together to make secure, interoperable business applications. Finally, the Java 2 Platform, Micro Edition (known as J2ME) is for consumer and embedded devices. These devices can include cell phones, PDAs, and vehicle telematic devices. Along with a robust development platform, Sun offers a robust education and certification program that Java developers can use to grow and certify their Java skills. Sun notes that each certification is developed to test on a certain job role for a Java developer. In the coming set of articles, you will dive deeper into the different Java certifications you can attain. Depending on your current job role or a job role you would like to hold, you will choose one or more certification paths that Sun has developed. The first Java 2 certification that one must attain to move forward in other Java certification paths is the Sun Certified Java Programmer Certification. As I just mentioned, all of the Java 2 certification programs are built from the Sun Certified Programmer Certification (SCJP). The following graphic from www.sun.com details the different certification paths that Java 2 programmers can follow, upon earning their SCJP credential. Sun wants all Sun Certified Professionals to pass this first certification because it demonstrates proficiency with the Java programming language. This is based on the J2SE platform. To achieve this credential, only one exam has to be passed. At the time of this writing, interested candidates can choose from one of five exams. Three of these exams are general exams for those who have not previously achieved a Java certification whereas two of these exams are upgrade exams. If you already have a previous Java certification, these upgrade exams allow you an efficient way to port your current skills to a different Java platform. Granted, just because you have passed one Java certification doesn't guarantee success on an upgrade exam. You will still need to brush up on old skills as well as learn the new features of the next Java version. The exams you can choose from include: For the remainder of this article, you can delve further into one of these exams, the J2SE Platform 5.0 exam. In coming articles, I will cover the 1.4 and 1.2 platform exams. As mentioned, this is a new Java exam. Just like the other exams one can pass to attain the SCJP credential, this exam is intended to examine the candidate on his abilities with fundamental Java tools and language syntax. The exam objectives for this exam include seven sections that break down the different features and structures of the J2SE 5.0 platform. These include: Some important facts to note about this exam include: Whether it is the J2SE Platform 5.0 SCJP certification or an A+ certification, much time and effort must be expended to prepare for the exam. For Sun Certification, Sun offers a deep training system that can help you prepare for you exams. The certification Web site at www.sun.com recommends several training classes for each exam they offer. Also, many computer book companies offer exam prep guides and general Java programming books one can use to prepare. The important thing to know is how you best learn, though. Do you learn best with a hands-on approach? Maybe you learn best by reading and taking notes. Possibly you prefer a classroom setting. Whichever method works best for you is the path you should follow. Set aside time and any other resource to give yourself 100% ability to pay attention to your study and preparation. After all, your career is being shaped by these efforts! Also, be sure to spend plenty of time taking practice exams. There are many vendors who offer questions. Also, the Sun Web site has links to practice questions as well. Spend plenty of time doing these practice exams to better gauge your learning progression and to build confidence for exam day. Developing a study plan, practicing diligently, and experiencing the Java 2, 5.0 Platform are key ingredients to successfully catching your SCJP certification.
Java 2 Certifications: An Introduction
August 16, 2005
The Sun Certified Java Programmer Certification

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Note: The exams for J2SE 5.0 are new offerings. As you can see, platforms 1.2, 1.4, and 5.0 are tested platforms. Choose the platform that best fits your needs or aspirations and pursue the individual exam that will help you achieve the SCJP certification.
Sun Certified Programmer for the Java 2 Platform, Standard Edition 5.0 (CX-310-055)
Note: The coverage above is only a quick look at the topics you will have to master. Be sure to check out the full list of exam objectives at www.sun.com/training/certification/java.
Studying for Certifications