Thread sampling is a hotspot detection method that works by periodically examining where in a program the executing threads spend their time. Typically, threads are stopped and their instruction pointers are cross-referenced against a table of known methods/regions. Enough samples in a given method means that the method is hot and should be optimized. Thread sampling can, if the number of samples is large enough, also be used on a more fine-grained level, determining which code paths or regions inside a method are hotter than others.