This repository contains an example about how to build OpenJDK 11 for Linux x86 (IA-32) on a Linux x86-64 system with Docker.
In the first step run sudo build-image.sh in order to create a Debian i386 root filesystem. You might use other already existing images from Docker Hub as well and update the Dockerfile accordingly. But I did not test this yet.
Afterwards execute build-openjdk.sh in order to start the build process. If everything went fine, the created OpenJDK packages are stored in the newly created package folder.