When waiting for a parser to complete its job in CCJSqlParser.parseStatement(CCJSqlParser) we call Future.get(long, TimeUnit) which clearly expects a long value to be passed, however the project does this:

statement = future.get( parser.getConfiguration().getAsInteger(Feature.timeOut), TimeUnit.MILLISECONDS);
Note the getAsInteger method.

Furthermore when using a custom value for the timeout setting it would be more convenient to just do:
CCJSqlParserUtil.parse(sql, parser -> parser.withTimeOut(TimeUnit.SECONDS.toMillis(30)))
instead of current:
CCJSqlParserUtil.parse(sql, parser -> parser.withTimeOut(Long.valueOf(TimeUnit.SECONDS.toMillis(30)).intValue()))