[antlr-interest] ANTLR Java.g and ver.jar

[Zachary Palmer]

Hello, all!  I have just downloaded the Java 1.6 grammar from the ANTLR 
site in hopes of performing some modifications for research purposes.  I 
am new to ANTLR, so the customary apologies for any silly queries 
applies.  :)  My issue is that the Java.g file provided on antlr.org 
contains the following comment:

 /*
    This is a merged file, containing two versions of the Java.g grammar.
    To extract a version from the file, run the ver.jar with the command 
provided below.
   
    Version 1 - tree building version, with all source level support, 
error recovery etc.
                This is the version for compiler grammar workspace.
                This version can be extracted by invoking:
                java -cp ver.jar Main 1 true true true true true Java.g
                            
    Version 2 - clean version, with no source leve support, no error 
recovery, no predicts,
                assumes 1.6 level, works in Antlrworks.
                This is the version for Alex.
                This version can be extracted by invoking:
                java -cp ver.jar Main 2 false false false false false 
Java.g
*/

It appears that this grammar file is used in a branch of the OpenJDK 
project, but the version I located on their site did not contain this 
comment; therefore, I am left to believe that it was inserted by the 
most recent author, Yang Jiang.  My trouble is that I have searched the 
OpenJDK project, ANTLR, and ANTLRWorks for a file named ver.jar to no avail.

When I try to load the grammar as-is into ANTLRWorks, I get a host of 
warnings of the following form:

[10:50:11] warning(209): Java.g:1771:1: Multiple token rules can match 
input such as "'*'": STAR, STAREQ

As a result, token(s) STAREQ were disabled for that input
[10:50:11] warning(209): Java.g:1811:1: Multiple token rules can match 
input such as "'i'": IF, IMPLEMENTS, IMPORT, INSTANCEOF, INT, INTERFACE, 
IDENTIFIER

As a result, token(s) 
IMPLEMENTS,IMPORT,INSTANCEOF,INT,INTERFACE,IDENTIFIER were disabled for 
that input

This eventually culminates in the following error:

[10:50:15] error(208): /home/zpalmer/research/Java.g:1799:1: The 
following token definitions can never be matched because prior tokens 
match the same input: 
INTLITERAL,DOUBLELITERAL,LINE_COMMENT,ASSERT,BREAK,BYTE,CATCH,CHAR,CLASS,CONST,CONTINUE,DO,DOUBLE,ENUM,EXTENDS,FINALLY,FLOAT,FOR,IMPLEMENTS,IMPORT,INSTANCEOF,INT,INTERFACE,NEW,PRIVATE,PROTECTED,PUBLIC,STATIC,STRICTFP,SUPER,SWITCH,SYNCHRONIZED,THROW,THROWS,TRANSIENT,TRY,VOLATILE,TRUE,FALSE,NULL,DOT,ELLIPSIS,EQEQ,PLUS,SUB,SLASH,AMP,BAR,PLUSEQ,SUBEQ,STAREQ,SLASHEQ,AMPEQ,BAREQ,CARETEQ,PERCENTEQ,BANGEQ

I'm at a loss as to how to proceed.  I would use the unmodified version 
of Java.g from the OpenJDK site, but it appears that the version hosted 
on the ANTLR website contains some valuable bug fixes.  Can anyone 
suggest a course of action or point me to a resource that might explain 
the above-described behavior?

Cheers,

Zachary Palmer