Abstract. Runtime verification can effectively increase the reliability of software systems. In recent years, parametric runtime verification has gained a lot of traction, with several systems proposed. However, lack of real specifications and prohibitive runtime overhead when checking numerous properties simultaneously prevent developers or users from using runtime verification. This paper reports on more than 150 formal specifications manually derived from the Java API documentation of commonly used packages, as well as a series of novel techniques which resulted in a new runtime verification system, RV-Monitor. Experiments show that these specifications are useful for finding bugs and bad software practice, and RV-Monitor is capable of monitoring all our specifications simultaneously, and runs substantially faster than other state-of-the-art runtime verification systems.