The technology contributes the inference of formal specifications automatically, which can increase the acceptance of specifications. The technology introduces the symbolic execution of a modifier method to explore its behavior and then summarizing the results of the exploration using observer methods. This often results in concise, understandable specifications, which are a prerequisite for human analysis. Optionally, a generated specification is deemed sound and or complete. The specifications are presented as traditional pre-/post-condition specifications or parameterized unit tests. The former often serve as inputs to a program verification system, whereas the latter often provide inputs for tools that generate test cases.