1. A virtual machine system residing on a native machine, the virtual machine system comprising: application code in a virtual machine specific format; native method code in a native machine specific format; a plurality of execution entities that operate portions of the application code and the native method code independently and in parallel; and an execution entity manager that assigns a portion of the native method code to an execution entity for execution; wherein the execution entity manager evaluates the potential behavior of the portion of the native method code, creates an execution entity of a first type and immediately assigns the execution entity of the first type to the portion of the native method code if the portion of the native method code has a first type of behavior, and creates an execution entity of the second type and immediately assigns the execution entity of the second type to the portion of the native method code if the portion of the native method code has a second type of behavior.