language tool for constructing recognizers, compilers etc (java library)

 ANTLR, ANother Tool for Language Recognition, (formerly PCCTS) is
 a language tool that provides a framework for constructing recognizers,
 compilers, and translators from grammatical descriptions containing C++
 or Java actions [You can use PCCTS 1.xx to generate C-based parsers].
 .
 This package contains the java libraries without a dependency on any runtime
 to be able to bootstrap gcj without a dependency on a java runtime.