JExpert is a free test simulation engine based on the latest pattern of Sun's Java Programmer Certification. The simulator contains a large number of questions and mock exams. For every question JExpert offers detailed explanations and pointers to resources for better understanding of the current topic. The simulator covers the objectives of both "Sun Certified Java 2 Programmer 1.2" and "Sun Certified Java 2 Programmer 1.4", such as declarations and access control, flow control and exception handling, garbage collection, language fundamentals, threads, assertions, collections, etc.