The Hotpath Virtual Machine is a research Java Virtual Machine developed at the University of California, Irvine. Its primary purpouse is aiding in the study of various aspects of Trace-Based Just-in-Time compilation.
The unit of compilation for traditional just-in-time compilers is the method. The Hotpath VM, explores the use of Trace-Based compilation, in which the unit of compilation is a loop, potentially spanning multiple methods and even library code. Using a new intermediate representation that is discovered and updated lazily on-demand while the program is being executed, the Hotpath VM compiler generates code that is competitive with traditional dynamic compilers, but that uses only a fraction of the compile time and memory footprint. For a more in depth introduction reffer to: One Method At A Time Is Quite a Waste of Time