How to change locale in Liberty Container image

So you got WebSphere Liberty Container image based on Ubuntu from here.
And you'd like to change locale because you'd like to have logs in another language, such as Japanese, etc.
My procedure in this post is based on this but I think you need some additional steps, so here is how.
By the way my environment is MacOS Monterey 23.6.5, Apple M1Pro,using podman instead of docker. That's why I pulled amd64, of course you can get other architecture images depending on your environment.

1.Make Containerfile to install JP locale package and set environment variables with root.

FROM docker.io/amd64/websphere-liberty:23.0.0.3-full-java17-openj9
USER 0
RUN apt-get update \
 && apt-get install -y language-pack-ja \
 && rm -rf /var/lib/apt/lists/*
ENV LANG=ja_JP.UTF-8 \
  LANGUAGE=ja_JP:ja \
  LC_ALL=ja_JP.UTF-8 \
  TZ="Asia/Tokyo"
USER 1001

2.Build image.

$ podman build -t amd64-websphere-liberty:23.0.0.3-full-java17-openj9-jp .
STEP 1/5: FROM docker.io/amd64/websphere-liberty:23.0.0.3-full-java17-openj9
STEP 2/5: USER 0
--> Using cache 5d96bfdaf8d57c662ee86745b993e848d14849982ab17d543c9a872dbd469da2
--> 5d96bfdaf8d
STEP 3/5: RUN apt-get update  && apt-get install -y language-pack-ja  && rm -rf /var/lib/apt/lists/*
Get:1 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Get:2 http://archive.ubuntu.com/ubuntu focal InRelease [265 kB]
Get:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Get:5 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages [2,632 kB]
Get:6 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages [1,275 kB]
Get:7 http://security.ubuntu.com/ubuntu focal-security/multiverse amd64 Packages [28.5 kB]
Get:8 http://security.ubuntu.com/ubuntu focal-security/universe amd64 Packages [1,035 kB]
Get:9 http://security.ubuntu.com/ubuntu focal-security/restricted amd64 Packages [2,145 kB]
Get:10 http://archive.ubuntu.com/ubuntu focal/multiverse amd64 Packages [177 kB]
Get:11 http://archive.ubuntu.com/ubuntu focal/restricted amd64 Packages [33.4 kB]
Get:12 http://archive.ubuntu.com/ubuntu focal/universe amd64 Packages [11.3 MB]
Get:13 http://archive.ubuntu.com/ubuntu focal-updates/multiverse amd64 Packages [31.2 kB]
Get:14 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [1,331 kB]
Get:15 http://archive.ubuntu.com/ubuntu focal-updates/restricted amd64 Packages [2,308 kB]
Get:16 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [3,125 kB]
Get:17 http://archive.ubuntu.com/ubuntu focal-backports/universe amd64 Packages [28.6 kB]
Get:18 http://archive.ubuntu.com/ubuntu focal-backports/main amd64 Packages [55.2 kB]
Fetched 26.2 MB in 20s (1,305 kB/s)
Reading package lists...
Reading package lists...
Building dependency tree...
Reading state information...
The following additional packages will be installed:
 language-pack-ja-base
The following NEW packages will be installed:
 language-pack-ja language-pack-ja-base
0 upgraded, 2 newly installed, 0 to remove and 3 not upgraded.
Need to get 1,673 kB of archives.
After this operation, 7,786 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 language-pack-ja-base all 1:20.04+20220818 [1,671 kB]
Get:2 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 language-pack-ja all 1:20.04+20220818 [1,900 B]
debconf: delaying package configuration, since apt-utils is not installed
Fetched 1,673 kB in 2s (899 kB/s)
Selecting previously unselected package language-pack-ja-base.
(Reading database ... 7344 files and directories currently installed.)
Preparing to unpack .../language-pack-ja-base_1%3a20.04+20220818_all.deb ...
Unpacking language-pack-ja-base (1:20.04+20220818) ...
Selecting previously unselected package language-pack-ja.
Preparing to unpack .../language-pack-ja_1%3a20.04+20220818_all.deb ...
Unpacking language-pack-ja (1:20.04+20220818) ...
Setting up language-pack-ja (1:20.04+20220818) ...
Setting up language-pack-ja-base (1:20.04+20220818) ...
Generating locales (this might take a while)...
 ja_JP.UTF-8... done
Generation complete.
--> 64f2583a73b
STEP 4/5: ENV LANG=ja_JP.UTF-8   LANGUAGE=ja_JP:ja   LC_ALL=ja_JP.UTF-8   TZ="Asia/Tokyo"
--> 7aade810f7c
STEP 5/5: USER 1001
COMMIT amd64-websphere-liberty:23.0.0.3-full-java17-openj9-jp
--> 78bbe9bddab
Successfully tagged localhost/amd64-websphere-liberty:23.0.0.3-full-java17-openj9-jp
78bbe9bddab06db1abaca8c6d0b8e2ca59908ea979ec07adb833714f50ed8d00

3.Run from the image and see if successfully running.

$ podman images
REPOSITORY                                   TAG               IMAGE ID   CREATED    SIZE
localhost/amd64-websphere-liberty                       23.0.0.3-full-java17-openj9-jp 78bbe9bddab0 6 seconds ago 828 MB

$ podman run -d -p 9080:9080 -p 9443:9443 --name libertypodman localhost/amd64-websphere-liberty:23.0.0.3-full-java17-openj9-jp
5194c9971675cf84ce8dc9b609c7c44b44ea74c5b3b29f421d68ba47a318a8ba

$ podman ps -a
CONTAINER ID IMAGE                               COMMAND        CREATED    STATUS    PORTS                      NAMES
5194c9971675 localhost/amd64-websphere-liberty:23.0.0.3-full-java17-openj9-jp /opt/ibm/wlp/bin/... 4 seconds ago Up 4 seconds 0.0.0.0:9080->9080/tcp, 0.0.0.0:9443->9443/tcp libertypodman

4.Check the inside of the container to check if JP locale is set and logs are written in JP.

$ podman exec -it libertypodman /bin/sh
$ locale -a
C
C.UTF-8
POSIX
en_US.utf8
ja_JP.utf8

$ locale
LANG=ja_JP.UTF-8
LANGUAGE=ja_JP:ja
LC_CTYPE="ja_JP.UTF-8"
LC_NUMERIC="ja_JP.UTF-8"
LC_TIME="ja_JP.UTF-8"
LC_COLLATE="ja_JP.UTF-8"
LC_MONETARY="ja_JP.UTF-8"
LC_MESSAGES="ja_JP.UTF-8"
LC_PAPER="ja_JP.UTF-8"
LC_NAME="ja_JP.UTF-8"
LC_ADDRESS="ja_JP.UTF-8"
LC_TELEPHONE="ja_JP.UTF-8"
LC_MEASUREMENT="ja_JP.UTF-8"
LC_IDENTIFICATION="ja_JP.UTF-8"
LC_ALL=ja_JP.UTF-8

$ cd logs
$ ls
messages.log
$ cat messages.log
********************************************************************************
product = WebSphere Application Server 23.0.0.3 (wlp-1.0.75.cl230320230319-1900)
wlp.install.dir = /opt/ibm/wlp/
server.output.dir = /opt/ibm/wlp/output/defaultServer/
java.home = /opt/java/openjdk
java.version = 17.0.6
java.runtime = IBM Semeru Runtime Open Edition (17.0.6+10)
os = Linux (5.17.5-300.fc36.aarch64; amd64) (ja_JP)
process = 1@5194c9971675
Classpath = /opt/ibm/wlp/bin/tools/ws-server.jar:/opt/ibm/wlp/bin/tools/ws-javaagent.jar
Java Library path = /opt/java/openjdk/lib/default:/opt/java/openjdk/lib:/usr/lib64:/usr/lib
********************************************************************************
[2023/04/26 14:21:22:376 JST] 00000001 com.ibm.ws.kernel.launch.internal.FrameworkManager      A CWWKE0001I: サーバー defaultServer が起動されました。
[2023/04/26 14:21:23:008 JST] 00000001 com.ibm.ws.kernel.launch.internal.FrameworkManager      A CWWKE0100I: この製品は、開発使用向け、および限定的な実動使用向けにライセンスが交付されています。 全ライセンス条項は以下で表示可能です: https://public.dhe.ibm.com/ibmdl/export/pub/software/websphere/wasdev/license/base_ilan/ilan/23.0.0.3/lafiles/ja.html
$ exit

Thanks.