PScript is an efficient larguage with dynamic loading and unloading support,small binary code size,good readability,and small memory footprint.

The method solves the boundary match problem for adjacent terrain blocks in dynamic loading which avoids "cracks" and rebuilds the whole terrain identically and seamlessly.

Java becomes the first choice due to its inherent advantages of platform independence, object serialization and dynamic class loading.

We present a fully formal, machine-checked specification of the bytecode verification and dynamic class loading, which are important parts in Java's security architecture.

Based on the practice of internet BBS programming, the writers put forward independent processing techniques for password checking pipe and DLM, which enables the BBS server to enlarge its on-line capacity almost three times at the best.