* [jvm-packages] add hostIp and python exec for rabit tracker (#7808) * Fix training continuation with categorical model. (#7810) * Make sure the task is initialized before construction of tree updater. This is a quick fix meant to be backported to 1.6, for a full fix we should pass the model param into tree updater by reference instead. Co-authored-by: Bobby Wang <wbo4958@gmail.com>