Java on Truffle is an implementation of the Java Virtual Machine Specification, Java SE 8 and Java SE 11, built upon GraalVM as a Truffle interpreter. It is a minified Java VM that includes all core components of a VM, implements the same API as the Java Runtime Environment library (libjvm.so), and reuses all JARs and native libraries from GraalVM. The project name behind this implementation is "Espresso". Its open source version is available on GitHub.