K-Java

Abstract

This paper presents K-Java, a complete executable formal semantics of Java 1.4. K-Java was extensively tested with a test suite developed alongside the project, following the Test Driven Development methodology. In order to maintain clarity while handling the great size of Java, the semantics was split into two separate definitions -- a static semantics and a dynamic semantics. The output of the static semantics is a preprocessed Java program, which is passed as input to the dynamic semantics for execution. The preprocessed program is a valid Java program, which uses a subset of the features of Java. The semantics is applied to model-check multi-threaded programs. Both the test suite and the static semantics are generic and ready to be used in other Java-related projects.

Formal Semantics for Java-like Languages and Research Opportunities

“…Java is distributed as part of the Java Development Kit (JDK) and currently is in the version 10. At the imperative level, this language has 38 operators (JLS §3.12), 18 statements ( §14), and some dozens of expressions ( §15), among other features, and is evolving over time [6]. A Java program can be represented by a combination of several of its features.…”

“…Indeed, there exist several studies on the formalization of parts of the Java language [8,9,10,11,6,14,15,16], and we have defined some criteria to select some of them to be presented in this text. Initially, we looked up for projects that describe the semantics of Java, particularly by structural operational semantics, filtering those that presented proofs of typesafety, both in formal or informal (non-mechanized) ways.…”

“…We should note that without a formal semantics it is impossible to state or prove anything about a language with certainty. For example, we cannot state that a program meets its specification, a type system is sound, or that a compiler or an interpreter is correct [6].…”

“…Indeed, there is a large body of literature on formal models of Java-like languages [8,9,10,11], where each of these models are designed to treat certain features of Java in depth, abstracting other features. Also, recently a complete executable semantics for an older version of Java was proposed [6], but without contemplating new important features.…”

Incremental parametric syntax for multi-language transformation

“…The C, Java, and Lua tests come from their respective implementations, while the JavaScript ones come from the official specification conformance test suite. The authors of K-Java report that no Java language tests are publicly available [4], and hence created their own specification tests, which we use. We restricted ourselves to the core language tests of test262, and omitted a small handful of multi-file Java tests among the Java ones, which caused problems with our test harness.…”