The present invention generates state machines that can be used in a scanner and/or a parser for software program compilation. The state machines are not table-driven, but rather are encoded directly by creating jumps and branches in bytecodes, which are machine-independent codes generated by a Java compiler and can be executed on any Java-enabled device. Such state machines can be much faster than those based on tables, and much smaller in code size than those implemented in executable codes. In addition, such state machines can be optimized to reduce the number of states and the amount of codes required to encode each state in it. This can allow these state machines to meet strict code size restrictions specified by certain virtual machines, such as the Java virtual machine.