OracleEnvironment throws an exception if the environment variable APP_USER is provided and the environment variable APP_PASSWORD isn't defined. As per the documentation for the gvenzl Oracle container here, the correct environment variable is APP_USER_PASSWORD. This means that in order to start a new gvenzl/oracle-xe container, both APP_PASSWORD and APP_USER_PASSWORD need to be defined in the compose file.

I have identified that this issue is present in 3.1.2 and 3.2.0-SNAPSHOT

services:
  oracle:
    image: 'gvenzl/oracle-xe:latest'
    environment:
      - ORACLE_PASSWORD=secret
      - APP_USER=appuser
      - APP_PASSWORD=secret_1
      - APP_USER_PASSWORD=secret_1
    ports:
      - '1521:1521'

The above starts correctly

services:
  oracle:
    image: 'gvenzl/oracle-xe:latest'
    environment:
      - ORACLE_PASSWORD=secret
      - APP_USER=appuser
      - APP_USER_PASSWORD=secret_1
    ports:
      - '1521:1521'

The above throws an exception on starting the application