This reproduces an issue with the Unix startup script generated by the Gradle application plugin.

Build the application with Docker:

docker build -t example .
docker run --env JAVA_OPTS="-Dfoo=bar" example

Expected behaviour

The application prints the following:

Application was started with -Dfoo=bar

Actual behaviour:

The application prints the following:

/example/bin/example: line 233: xargs: command not found
Application was started with -Dfoo=null