Java Data Objects (JDO) is a standard way to access persistent data in databases, using plain old Java objects (POJO) to represent persistent data. The approach separates data manipulation (done by accessing Java data members in the Java domain objects) from database manipulation (done by calling the JDO interface methods). This separation of concerns leads to a high degree of independence of the Java view of data from the database view of the data.
GraalVM as a PlatformGraalVM is an open ecosystem and allows users to implement a custom language or tool on top of it with the Truffle language implementation framework which offers APIs for writing interpreters for programming languages in the form of Java programs.
Truffle Language Implementation FrameworkThe Truffle language implementation framework (Truffle) is an open source library for building tools and programming languages implementations as interpreters for self-modifying Abstract Syntax Trees.
Wikipedia / Java Modeling Languageis a specification language for Java programs, using Hoare style pre- and postconditions and invariants, that follows the design by contract paradigm.