public Configuration getConfiguration(final String groupId) {
        Requires.requireTrue(!StringUtils.isBlank(groupId), "Blank group id");

        final GroupConf gc = this.groupConfTable.get(groupId);
        if (gc == null) {
            return null;
        }
        final StampedLock stampedLock = gc.stampedLock;
        long stamp = stampedLock.tryOptimisticRead();
        Configuration conf = gc.conf;
        if (!stampedLock.validate(stamp)) {
            stamp = stampedLock.readLock();
            try {
                conf = gc.conf;
            } finally {
                stampedLock.unlockRead(stamp);
            }
        }
        return conf;
    }
Get the configuration by groupId, returns null when not found.

@param groupId raft group id
@return configuration of the group id
jraft-core/src/main/java/com/alipay/sofa/jraft/RouteTable.java