Kohsuhe Kawaguchi has announced a Java interface specification for RELAX processors, and Daisuke Okajima has created RelaxNGCC, a Java class generator for RELAX NG schemas.

Kawaguchi's specification, hosted on the SourceForge iso-relax project, consists of a set of Java interfaces. JavaDoc documentation is available. Two RELAX processors currently implement the interfaces: RELAX Verifier for Java, and the Sun Multi-Schema XML Validator.

Okajima's RelaxNGCC generates Java source code from a RELAX NG grammar. Taking an approach similar to that of yacc, RelaxNGCC allows the programmer to embed pieces of source code inside the grammar to affect the behavior of the processing.