Wikipedia
picoJava is a microprocessor specification dedicated to native execution of Java bytecode without the need for an interpreter or just-in-time compilation. The aim is to speed bytecode execution up by up to 20 times, compared to standard Intel CPU with a Java Virtual Machine. picoJava-based microprocessors can also execute C/ C++ code as efficiently as comparable RISC CPU architectures. This approach results in the fastest Java runtime performance with a small memory footprint and competitive performance on code not written in the Java language.
The picoJava specification does not include any memory or I/O interface logic, so that developers can add their own logic to customize memory and an interface.