private GroupConf getOrCreateGroupConf(final String groupId) {
        GroupConf gc = this.groupConfTable.get(groupId);
        if (gc == null) {
            return this.groupConfTable.computeIfAbsent(groupId, key -> new GroupConf());
        }
        return gc;
    }
Update configuration of group in route table.

@param groupId raft group id
@param conf    configuration to update
@return true on success
jraft-core/src/main/java/com/alipay/sofa/jraft/RouteTable.java